Book 1 to 5

Book6

(Name meaning here)

Nick names

Snivellus
(named by the Marauders) May have been because he used to snivel or cry, or because of his large hooked nose

Greasy Git (students)

Overgrown Bat (Quirell)

Snape (degoratorily used  by students)

old Snape
Git (Weasley twins)

Lucius Malfoy's lapdog (Sirius)

38 and 5 months
(end of Book6 - June 1996)

British
(inference/deduction: no mention of any type of accent in the books and Alan Rickman uses a very well defined British accent in the movies)

Half-blood

 Unknown

 No known spouse or children

No known siblings
Tobias Snape - muggle
-hook-nosed man
-sounds abusing
Eileen Prince - witch
-Captain of the Hogwarts Gobstones Team in her school years.
-Described as a skinny girl, not pretty; looking simultaneously cross and sullen, with heavy brows and a long, pallic face.
-Described once as cowering from her shouting husband while Severus cried in a corner

Unknown whether they are still alive or not

Childhood Residence

Unknown
Inference: "a greasy-haired teenager sat alone in a dark bedroom, pointing his wand at the ceiling, shooting down flies… "
This can lead us to believe it was his house as a child.

Wonderful description by HP Lexicon

More details and Pictures of what could probably be Spinner's End in reality (thanks to Afictionado!)

We do not know if this is only a hideout or his real propriety.  Speculation has it that Spinner's End may be Snape's childhood residence in a now abandoned run-down Muggle neighbourhood. May date from the weaving and spinning industrial age that ended in the 1960's due to Asian competition. Cobbled streets are often a good indicator of the property's age.

Most probable location: North or West Yorkshire, or Lancashire.  However, Snape shows no evidence of any local accent.

He seems okay with living in such a filthy place in Book6 and doesn't complain about it.

Education - Childhood

Unknown though Rowling did say this: "They (children of wizards) are, as many of you have guessed, most often home educated. With very young children, as you glimpsed at the wizards' camp before the Quidditch World Cup in 'Goblet of Fire', there is the constant danger they they will use magic, whether inadvertently or deliberately; they cannot be trusted to keep their true abilities hidden. Even Muggle-borns like Harry attract a certain amount of unwelcome attention at Muggle schools by regrowing their hair overnight and so on."

In Severus' case, since he was so well versed and seemingly practiced into curses and the Dark Arts from the start at Hogwarts, we can presume such a home education took place.

Appearance and clothing -  Childhood

Dark-haired

See a detailed timeline of the crucial events in Severus Snape's life

Student at Hogwarts

Snape enters Hogwarts on September 1st, 1970.
He graduates in 1977 at 18 years old.

He is sorted into Slytherin House (officiated by Rowling).
Professor Horace Slughorn is the Head of House from 1938 to 1980.
The Marauders (James, Sirius, Lupin and Pettigrew) and Lily Evans enter Hogwarts
Lucius Malfoy is entering his 6th year.

"Snape knew more curses when he arrived at school than half the kids in seventh year, and he was part of a gang of Slytherins who nearly all turned out to be Death Eaters." (Sirius)

Snape was clearly unpopular and called names. Snape was just this little oddball. James even said that he kept annoying and attacking him because 'it's more the fact that he exists, if you know what I mean…'

Appearance and clothing - Teenager

Body: scrawny boy, stringy (lean), skinny, pallid legs, like a plant kept in the dark, round-shoulders yet angular.

Face: Hooked nose

Skin: pallid look. By Sirius: "slimy, oily kid"

Hair: Lank (hanging straight and limp without spring or curl) and greasy hair flopping (to swing or move loosely )on to the table, oily hair was jumping about his face.

Demeanor/Walk: twitchy manner that recalled a spider. While writing: writes very fast (his hand was flying over the parchment) and very close to the parchment, hunched over it. His calligraphy was minuscule and cramped.

Clothing: Hogwarts robes and a pair of greying underpants

Socioeconomic Level as a child and student

Inference: from the state of his clothes and description of his 'dark bedroom', it is safe to assume his family was not rich having nothing else to play with but flies.

 Appearance - Adult

• Height: Sirius was rather taller than Snape
• Weight: unknown though he is described as a thin man
• Distinguishing feature: his Dark Mark on his left forearm
• Color preference: Black!
• Health: (inference) good and in good shape. He can easily run up the stairs and can sustain painful injuries (like Fluffy's nasty bite!).
  

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Hands: long thin fingers

Skin: sallow skin (means "grayish greenish yellow color")
When angry, it turns to the color of sour milk, "looked paler than usual"

Face: pallid face, thin, sallow, uneven and yellowish teeth, a vein flickering horribly on his greasy temple when furious, expression often unfathomable, lips often curled when talking, "Snape's lips were shaking, his face was white, his teeth were bared" when furious beyond reason, very grim smile

Nose: hooked nose, very crooked nose, prominent nose, overlarge nose, long over-large nostrils. Tonks' nose swelled to a beak-like protuberance that resembled Snape's 

Eyes: Black eyes with no warmth in them, cold and empty, like dark tunnels, flashing dangerously, fathomless, "black like Hagrid’s, but they had none of Hagrid’s warmth. They were cold and empty and made you think of dark tunnels", "cold black eyes fixed unblinkingly", narrowed eyes when suspicious, "loathing in his eyes"

Eyebrows: famous for his raised eyebrow(s)

Hair: long shoulder-length greasy black hair, curtain(s) of greasy black hair

Voice: very cold voice, sneering, dangerous, more and more quietly waspish when aimed to hurt or argue, silky, sleek, often sounding cold and unconcerned, contemptuous, will talk slowly and deliberately as though to weight every word (Slytherin), spats, sharp voice,

Demeanor/Walk: prowling kind of walk,gliding over like a large and malevolent bat, "Snape pocketed his wand, turned on his heel and swept back". Inference: stealth because he is often found  behind students before they realise he's there. Often seen as a military and/or graceful.

Clothing - Adult

Teaching robes: black robes rippling in a cold breeze, there is at least one inner pocket for his wand and at least one small bottle (Veritaserum) though the bottle may be kept in another pocket.

A long black traveling cloak with a pocket where he stores his wand. The cloak billows behind him

Slytherin Quidditch Team partisanship: "Professor Snape sat in the very front row, wearing green like everyone else"

Night attire: a long gray nightshirt

Educational Background: Master of Potions (it is unknown whether he studied as an apprentice after graduating from Hogwarts.

Intelligence Level: very clever and educated. His speech patterns also reveals his intellectual aptitudes. Logical!

• Snape has quite a memory
• Snape has an incredible sense of deduction  
Snape's mere presence is usually enough to ensure a class's silence.
Hhe is the only one aware of Harry Potter's pranks or hidden intentions apart from all-knowing-Albus. 
He is subtle and understands all the finer distinctions (Told Harry: "You do not understand fine distinctions. It is one of the shortcomings that makes you such a lamentable potion-maker.')

More Personality traits here (loads!)

Patronus

Boggart

JKRowling refused to reveal them saying it would ruin the final plot : (

However, we can suppose his animal is not a weak one because he dared tell Tonks that her new Patronus looked weak. Also, since the patronus could reveal too much about Snape, it somehow entice that it would also reveal too much to the Order members. Is it why some are weary of him already? Or is it the reason why they were shocked when he killed Dumbledore because they never thought he would?

Magical Powers/Abilities

Great abilities at wordless magic: "He clicked his fingers, and the ends of the cords that bound Lupin flew to his hands. "I'll drag the werewolf." "Snape had directed his wand straight at James; there was a flash of light and a gash appeared on the side of James's face, spattering his robes with blood."

Occlumency: "he is a superb Occlumens". Snape has survived Voldemort's Legilimency on him, hence he is better at Occlumens compared to the skills of the Dark Lord in Legilimency. However, Albus is said to be better than any Occlumens. "Only those skilled at Occlumency are able to shut down those feelings and memories that contradict the lie, and so can utter falsehoods in his presence without detection.'

Legilimency (Legilimency is easier when the spell-caster is physically near the target, and when the target is off-guard, relaxed, or otherwise vulnerable. ) Therefore, we can speculate that Snape is always on-guard, not relaxed nor vulnerable when he meets with the Dark Lord or other Death Eaters. He is able to retain his coolness and senses.  This is one reason why he reminds us of a well trained military officer.

Dueling: very quick and efficient in a duel against someone. Knows the rules and concept of Wizard Dueling.

Thestrals: Rowling said it was obvious that he could see them. Hence, he's seen and understood the pain of death.  

Curses: "Snape knew more curses when he arrived at school than half the kids in seventh year, and he was part of a gang of Slytherins who nearly all turned out to be Death Eaters."

Dark Arts: Potter was very good at them and it was said Snape was up to his eyes in the Dark Arts. Snape's always been fascinated by the Dark Arts, he was famous for it at school.

Spells he invented as a teenager:

• Sectumsempra
• Langlock
  (A jinx that glues the target's tongue to the roof of his or her mouth)
• Levicorpus
  (Dangles the target person upside-down by the ankle in mid-air.)
• Liberacorpus (Counter-jinx to levicorpus)
• Muffliato (Fills the ears of target persons near the caster with an unidentifiable buzzing, so that the caster can hold lengthy conversations without being overheard.)
• toenail-growing hex (Causes the target's toenails to grow alarmingly fast.)

Spells he used in the books:

• Serpensortia
• Finite Incantatem
• Apparate and Disapparate
• Avada Kedavra "Never used an Unforgivable Curse before, have you, boy? You need to mean them, Potter! You need to really cause pain--to enjoy it-- righteous anger won't hurt me for long..." Righteous anger will hurt someone but not for long unless the caster really means it. The same must apply to killing and Imperio. Was Snape serious about killing Dumbledore or was the fall the real cause of his death?
• Incarcerous
• Conjuring a stretcher
• Expelliarmus
• Lumos
• Nonverbal spell to open doors
• Evanesco : to clean away a mess or empty a cauldron
• Fidelius Charm applied to the headquarters of the Order of the Phoenix, but he was not the Secret Keeper
• Unnamed spell Dumbledore and Snape cast to lock and unlock the gates
• Unnamed spell Snape uses to heal Malfoy of the Sectumsempra
• Unbreakable Vow: needs three people, two swearing and one binder using a wand. The vowers must touch hands and the bonder touch them using a wand. Breaking one's promise means immediate death. Snape swore an Unbreakable Vow to Narcissa Malfoy with Bellatrix Lestrange as Bonder

Potions

He can brew any potions he want, including the very hard to make Wolfsbane potion to allow Remus Lupin to avoid transforming into a wild untamed werewolf come the full moon.

Snape rewrote a high school level potions book by himself with much simpler instructions and perfect results, better than the school book. Hence we can assume he is truly a genius at it.  However, we could wonder why he never used his own recipes in class. He forgot that book, the Half-Blood Prince's book in the old Potions Storeroom in the Potions classroom.

Wolfsbane

Flaws

Mental Illnesses: some speculate that he suffers from chronic depressive moods.

Snape seems himself much lesser in terms of magical abilities than Albus and Voldemort. He seems to consider it a flaw. "Dumbledore is an extremely powerful wizard,' Snape muttered. 'While he may feel secure enough to use the name… the rest of us…"

Can be very unfair  though he sometimes does that in order to require pay back from an offence that went unpunished by someone else.

He loses his temper when people disrespect him or contradict him.

Not a natural talent at Quidditch. "a girl was laughing as a scrawny boy tried to mount a bucking broomstick" even though he referred for one match, he was not very quick to avoid Potter when he came flying his way which may indicate that he's got no natural talent for it.

more here!

(in order of importance)

 When with the Light side

Albus Dumbledore
Minerva McGonagall
Hagrid
Order of the Phoenix

When with the Dark side

Lucius Malfoy
Death Eaters
Voldemort

See HP Lexicon's short list on Snape's true allegiances

OPPOSITE of Allies

In Book6, his allies on the Light side are null unless someone knows something the members of the Order do not.  All the Wizarding World (Ministry, citizens, etc) will consider him a number one public enemy.

Fears / Pet peeves

Voldemort

Saying the Dark Lord's name or hearing it

Being uncovered as a spy (on both sides)

Having his most important memories discovered (Pensieve)

Humiliation or public disrespect towards his person

Having his authority overthrown

 BOOK6: Being caught and killed before he can try to explain his point of view

JKRowling having a disease that incapacitates her to fnish Book7 (Oops! that's OUR worst fear ; )

Objects associated with Snape

Quarters in the dungeons of Hogwarts.
Summer residence unknown

Spinner's End residence or hideout
(click for more information)

Inference: lives on a professor' salary and may get some more for being Head of House. Salary unknown though being a Master, teachers of Hogwarts must not be so badly treated or so we hope.

Snape has never been described, as an adult, as wearing torn or old robes.  Therefore, we may assume he takes care of that aspect using his money.

We do not know if Snape has an house-elf or if he owns a real propriety. He lives in Spinner's End in Book6 (or has been for years) but we do not know if this is only a hideout or his propriety.  He seems okay with living in such a filthy place.

Habits

He rubs his Dark Mark, apparently unconsciously, when people talk about it or accuse him personally

 Giving out detention or make Gryffindor lose House points

When reflecting, he once traced his mouth with his finger. May prove an habit.

No known abuse of any substances

Hobbies

 No known hobbies

Though he did say once 'You do know why I am giving up my evenings to this tedious job?, therefore suggesting that he has other things to do than being a teacher or guardian at night.

Excellent Potion maker

Exacting Potion Master

Excellent spy

Defence Against the Dark Arts teacher

As a teacher, to make sure all dunderheads get as high marks as possible. Especially on the OWL and NEWTS

As a Potter-hater, to get him expelled when he does stupid unacceptable things or punish him as much as he can for his faults

Win the House Cup and the Quidditch Cup for Slytherin each year

After the murder of Dumbledore:

 Live in hiding and not be discovered before the truth is unveiled

Staying in the good graces of Voldemort so he doesn't dispose of him since he can't go back to the Order

Reach his unknown goal (be it for the Light or the Dark side or himself)

 Motto or guidelines in life

Fools who wear their hearts proudly on their sleeves, who cannot control their emotions, who wallow in sad memories and allow themselves to be provoked so easily - weak people, in other words - they stand no chance against his powers! He will penetrate your mind with absurd ease, Potter!'

Snape's guidelines to life (as per deduction):

If you can't control yourself, than you're other people's food.
If you have no control, you are weak and a fool for allowing others to take advantage of you
Stop wallowing and get on with life
Only you can hand over or not control of your emotions to others (provocation)
Being proud can bring one to over estimate their capacities and believe everyone will react the same way

Teaching views and relationship skills

Confident, proud, introverted, acts logically most of the time, not prone to socialise at all, hates being disturbed, hates laziness, sarcastic with almost everyone

Seems to hate teaching though I say he simply hates teaching stupid students who won't put in their 100%.

Believes most students are dunderheads and exacts the maximum they can give. "But we have another year to go before that happy moment of farewell" "I take only the very best in my NEWTS class"

Hated for his teaching methods and often called unfair. The other teachers always have to remind the kids to refer to him using his title.

Requires all students or lower authority figures to call him sir or professor. Doesn't like to be called Severus (like when Fudge called him so) "I told you,' said Snape, rigid in his chair, his eyes slits, 'to call me "sir".'

Often taunts and makes snide remarks

Uses body language while teaching or expressing his intentions.

Snape is introverted and hates being nagged.  He is impatient with most people. "Snape was as unpleasant as ever. His mood was further lowered by the DA members constantly approaching him in the corridors between classes, asking hopefully if there would be a meeting that night."

"Deliberately causing mayhem in Snape's Potions class was about as safe as poking a sleeping dragon in the eye."

Snape's upper lip was curling. Harry wondered why Lockhart was still smiling; if Snape had been looking at him like that he'd have been running as fast as he could in the opposite direction.

Snape was looking as though the first person to ask him for a Love Potion would be force-fed poison.