Real Dictionary

snuff
uncountable noun: Snuff is powdered tobacco which people take by breathing it in quickly through their nose.
verb: If someone snuffs it, they die.

snuff in American English 1
designating or of a kind of pornographic film that shows someone being murdered as the climax of sexual activity
the charred end of a candlewick
to trim off the charred end of (a candlewick)
intransitive verb: to draw air into the nostrils by inhaling, as to smell something; snuffle
noun: an act of snuffing; an inhalation through the nose; a sniff
transitive verb: to draw in through the nose by inhaling

snuff in American English 2
the act or sound of snuffing; sniff
to draw in through the nose; inhale strongly; sniff
to sniff or snort
noun: the charred or partly consumed portion of a candlewick
transitive verb: to cut off or remove the snuff of (candles, tapers, etc)

snuff in British English 1
noun: an act or the sound of snuffing
verb: to inhale through the nose

snuff in British English 2
noun: finely powdered tobacco for sniffing up the nostrils or less commonly for chewing

snuff in British English 3
to extinguish (a light from a naked flame, esp a candle)