Gri*mace" (gr&ibreve;*mās"), n. [F., prob. of Teutonic origin; cf. AS. grīma mask, specter, Icel. grīma mask, hood, perh. akin to E. grin.] A distortion of the countenance, whether habitual, from affectation, or momentary and occasional, to express some feeling, as contempt, disapprobation, complacency, etc.; a smirk; a made-up face.
[1913 Webster]

Moving his face into such a hideous grimace, that every feature of it appeared under a different distortion.

&fist; "Half the French words used affectedly by Melantha in Dryden's "Marriage a-la-Mode," as innovations in our language, are now in common use: chagrin, double-entendre, éclaircissement, embarras, équivoque, foible, grimace, naïvete, ridicule. All these words, which she learns by heart to use occasionally, are now in common use." I. Disraeli.
[1913 Webster]

Gri*mace", v. i. To make grimaces; to distort one's face; to make faces. H. Martineau.

• A distortion of the countenance, whether habitual, from affectation, or momentary and occasional, to express some feeling, as contempt, disapprobation, complacency, etc.; a smirk; a made-up face.
       quotations:
       *"I trundle off to bed, eyes brimming, face twisted into a grateful glistening grimace, and awaken the next day wondering what all the fuss was about." — Opera News, March 2005
  
• To make grimaces; to distort one's face; to make faces.