Source : Webster's Revised Unabridged Dictionary (1913)

Smirk \Smirk\, v. i. [imp. & p. p. {Smirked}; p. pr. & vb. n.
   {Smirking}.] [OE. smirken, ASS. smercian, smearcian; cf. MHG.
   smieren, smielen, to smile. See {Smile}, v. i.]
   To smile in an affected or conceited manner; to smile with
   affected complaisance; to simper.

Smirk \Smirk\, n.
   A forced or affected smile; a simper.

         The bride, all smirk and blush, had just entered. --Sir
                                                  W. Scott.

Smirk \Smirk\, a.
   Nice,; smart; spruce; affected; simpering. ``So smirk, so
   smooth.'' --Spenser.

Source : WordNet®

smirk
     n : a smile expressing smugness or scorn instead of pleasure
     v : smile affectedly or derisively [syn: {simper}]