Source : Webster's Revised Unabridged Dictionary (1913)

Fawn \Fawn\, v. i. [imp. & p. p. {Fawned}; p. pr. & vb. n.
   {Fawning}.] [OE. fawnen, fainen, fagnien, to rejoice,
   welcome, flatter, AS. f[ae]gnian to rejoice; akin to Icel.
   fagna to rejoice, welcome. See {Fain}.]
   To court favor by low cringing, frisking, etc., as a dog; to
   flatter meanly; -- often followed by on or upon.

         You showed your teeth like apes, and fawned like
         hounds.                                  --Shak.

         Thou with trembling fear, Or like a fawning parasite,
         obeyest.                                 --Milton.

         Courtiers who fawn on a master while they betray him.
                                                  --Macaulay.