Source : Webster's Revised Unabridged Dictionary (1913)

Snift \Snift\, v. i. [imp. & p. p. {Snifted}; p. pr. & vb. n.
   {Snifting}.] [From {Sniff}.]
   1. To snort. [Obs.] ``Resentment expressed by snifting.''
      --Johnson.

   2. To sniff; to snuff; to smell.

            It now appears that they were still snifing and
            hankering after their old quarters.   --Landor.

Snifting \Snift"ing\,
   a. & n. from {Snift}.

   {Snifting valve}, a small valve opening into the atmosphere
      from the cylinder or condenser of a steam engine, to allow
      the escape of air when the piston makes a stroke; -- so
      called from the noise made by its action.