Source : Webster's Revised Unabridged Dictionary (1913)

Grotesque \Gro*tesque\, n.
   1. A whimsical figure, or scene, such as is found in old
      crypts and grottoes. --Dryden.

   2. Artificial grotto-work.

Source : WordNet®

grotesque
     adj 1: distorted and unnatural in shape or size; abnormal and
            hideous; "tales of grotesque serpents eight fathoms
            long that churned the seas"; "twisted into monstrous
            shapes" [syn: {monstrous}, {unnatural}]
     2: ludicrously odd; "Hamlet's assumed antic disposition";
        "fantastic Halloween costumes"; "a grotesque reflection in
        the mirror" [syn: {antic}, {fantastic}, {fantastical}]

grotesque
     n : art characterized by an incongruous mixture of parts of
         humans and animals interwoven with plants