The Collaborative International Dictionary of English v.0.48:

Snuff \Snuff\, v. t. [imp. & p. p. Snuffed; p. pr. & vb. n.
   Snuffing.] [OE. snuffen. See Snuff of a candle Snuff to
   sniff.]
   To crop the snuff of, as a candle; to take off the end of the
   snuff of.
   [1913 Webster]

   To snuff out, to extinguish by snuffing.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Snuff \Snuff\, v. t.[Akin to D. snuffen, G. schnupfen,
   schnuppen, to snuff, schnupfen a cold in the head, schnuppen
   to snuff (air), also, to snuff (a candle). Cf. Sniff,
   Snout, Snub, v. i.]
   1. To draw in, or to inhale, forcibly through the nose; to
      sniff.
      [1913 Webster]

            He snuffs the wind, his heels the sand excite.
                                                  --Dryden.
      [1913 Webster]

   2. To perceive by the nose; to scent; to smell.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Snuff \Snuff\, v. i.
   1. To inhale air through the nose with violence or with
      noise, as do dogs and horses. --Dryden.
      [1913 Webster]

   2. To turn up the nose and inhale air, as an expression of
      contempt; hence, to take offense.
      [1913 Webster]

            Do the enemies of the church rage and snuff? --Bp.
                                                  Hall.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Snuff \Snuff\, n. [Cf. G. schnuppe candle snuff, schnuppen to
   snuff a candle (see Snuff, v. t., to snuff a candle), or
   cf. Snub, v. t.]
   The part of a candle wick charred by the flame, whether
   burning or not.
   [1913 Webster]

         If the burning snuff happens to get out of the
         snuffers, you have a chance that it may fall into a
         dish of soup.                            --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Snuff \Snuff\, n.
   1. The act of snuffing; perception by snuffing; a sniff.
      [1913 Webster]

   2. Pulverized tobacco, etc., prepared to be taken into the
      nose; also, the amount taken at once.
      [1913 Webster]

   3. Resentment, displeasure, or contempt, expressed by a
      snuffing of the nose. [Obs.]
      [1913 Webster]

   Snuff dipping. See Dipping, n., 5.

   Snuff taker, one who uses snuff by inhaling it through the
      nose.

   To take it in snuff, to be angry or offended. --Shak.

   Up to snuff, not likely to be imposed upon; knowing; acute.
      [Slang]
      [1913 Webster]

WordNet (r) 3.0 (2006):

snuff
    adj 1: snuff colored; of a greyish to yellowish brown [syn:
           snuff, snuff-brown, mummy-brown, chukker-brown]
    n 1: the charred portion of a candlewick
    2: a pinch of smokeless tobacco inhaled at a single time
    3: finely powdered tobacco for sniffing up the nose
    4: sensing an odor by inhaling through the nose [syn: sniff,
       snuff]
    v 1: sniff or smell inquiringly [syn: snuff, snuffle]
    2: inhale audibly through the nose; "snuff coke"

Moby Thesaurus II by Grady Ward, 1.0:

137 Moby Thesaurus words for "snuff":
   Aqua-Lung, artificial respiration, aspirate, aspiration,
   assibilate, assibilation, asthmatic wheeze, blow, blow out, breath,
   breath of air, breathe, breathe hard, breathe in, breathe out,
   breathing, broken wind, buzz, choke, cough, damp, douse, draw in,
   dudgeon, effervesce, effervescence, effervescing, exhalation,
   exhale, exhaust, expel, expiration, expire, exsufflation,
   extinguish, fizz, fizzle, fizzling, frication, frictional rustling,
   gasp, gulp, hack, hiccup, hiss, hissing, huff, hush, hushing,
   inhalation, inhalator, inhale, inhalement, inspiration, inspire,
   insufflation, iron lung, lisp, miff, mouth-to-mouth resuscitation,
   nose, out, oxygen mask, oxygen tent, pant, pinch of snuff, pique,
   puff, put out, quench, rappee, resentment, respiration, respire,
   rhonchus, scent, scuba, shush, shushing, sibilance, sibilate,
   sibilation, siffle, sigh, sigmatism, siss, sissing, sizz, sizzle,
   sizzling, slack, slurp, smell, smell of, smother, sneeze, sneezing,
   sniff, sniffle, snoose, snore, snoring, snort, snuff bottle,
   snuff in, snuff mill, snuff out, snuffbox, snuffle, spit, splutter,
   sputter, squash, squelch, squish, stamp out, sternutation, stertor,
   stifle, suck, suck in, sucking, suckle, suction, suspiration,
   swish, umbrage, wheeze, whiff, whish, whistle, whistling,
   white noise, whiz, whoosh, wind, zip