The Collaborative International Dictionary of English v.0.48:

Sniffing \Sniff"ing\, n. (Physiol.)
   A rapid inspiratory act, in which the mouth is kept shut and
   the air drawn in through the nose.
   [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]