The Collaborative International Dictionary of English v.0.48:

Sniff \Sniff\, v. t.
   1. To draw in with the breath through the nose; as, to sniff
      the air of the country.
      [1913 Webster]

   2. To perceive as by sniffing; to snuff, to scent; to smell;
      as, to sniff danger.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sniff \Sniff\, n.
   The act of sniffing; perception by sniffing; that which is
   taken by sniffing; as, a sniff of air.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sniff \Sniff\, v. i. [imp. & p. p. Sniffedor Snift; p. pr. &
   vb. n. Sniffing.] [OE. sneven; akin to snivel, snuff; cf.
   Dan. snive to sniff. See Snuff, v. t.]
   To draw air audibly up the nose; to snuff; -- sometimes done
   as a gesture of suspicion, offense, or contempt.
   [1913 Webster]

         So ye grow squeamish, gods, and sniff at heaven. --M.
                                                  Arnold.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sniff
    n 1: sensing an odor by inhaling through the nose [syn: sniff,
         snuff]
    v 1: perceive by inhaling through the nose; "sniff the perfume"
         [syn: sniff, whiff]
    2: inhale audibly through the nose; "the sick student was
       sniffling in the back row" [syn: sniff, sniffle]

Moby Thesaurus II by Grady Ward, 1.0:

138 Moby Thesaurus words for "sniff":
   Aqua-Lung, artificial respiration, aspirate, aspiration,
   assibilate, assibilation, asthmatic wheeze, be warm, blow, breath,
   breath of air, breathe, breathe hard, breathe in, breathe out,
   breathing, broken wind, burn, buzz, cough, cut, cut direct,
   disregard, draw in, effervesce, effervescence, effervescing,
   exhalation, exhale, exhaust, expel, expiration, expire,
   exsufflation, feeling, fizz, fizzle, fizzling, frication,
   frictional rustling, gasp, get wind of, gulp, hack, hiccup, hint,
   hiss, hissing, huff, humiliation, hush, hushing, inhalation,
   inhalator, inhale, inhalement, inspiration, inspire, insufflation,
   iron lung, lisp, mouth-to-mouth resuscitation, nose, nose out,
   odor, oxygen mask, oxygen tent, pant, puff, rebuff, repulse,
   respiration, respire, rhonchus, scent, scuba, shush, shushing,
   sibilance, sibilate, sibilation, siffle, sigh, sigmatism, siss,
   sissing, sizz, sizzle, sizzling, slight, slurp, smell, smell of,
   smell out, sneer, sneeze, sneezing, sniff at, sniff out, sniffle,
   snore, snoring, snort, snub, snuff, snuff in, snuffle, spirit,
   spit, splutter, spurn, spurning, sputter, squash, squelch, squish,
   sternutation, stertor, suck, suck in, sucking, suckle, suction,
   suggestion, suspiration, swish, the cold shoulder, the go-by,
   wheeze, whiff, whish, whistle, whistling, white noise, whiz,
   whoosh, wind, zip



The Jargon File (version 4.4.7, 29 Dec 2003):

sniff
 v.,n.

    1. To watch packets traversing a network. Most often in the phrase packet
    sniffer, a program for doing same. 2. Synonym for poll.


The Free On-line Dictionary of Computing (30 December 2018):

poll
polling
sniff

   To check the status of an input line, sensor, or memory
   location to see if a particular external event has been
   registered.

   Contrast interrupt.

   [Jargon File]

   (1995-01-31)


The Free On-line Dictionary of Computing (30 December 2018):

Sniff

   A C++/C programming environment providing browsing,
   cross-referencing, design visualisation, documentation and
   editing support.  Developed by UBS Switzerland and marketed by
   takeFive Salzburg.

   [Jargon File]