From WordNet (r) 2.0 (August 2003) [wn]:
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]
n : art characterized by an incongruous mixture of parts of
humans and animals interwoven with plants
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Grotesque \Gro*tesque"\ (gr[-o]*t[e^]sk"), a. [F., fr. It.
grottesco, fr. grotta grotto. See Grotto.]
1. Like the figures found in ancient grottoes; grottolike.
[1913 Webster]
2. Hence: Wildly or strangely formed; whimsical; extravagant;
of irregular forms and proportions; fantastic; ludicrous;
antic. "Grotesque design." --Dryden. "Grotesque
incidents." --Macaulay.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Grotesque \Gro*tesque\, n.
1. A whimsical figure, or scene, such as is found in old
crypts and grottoes. --Dryden.
[1913 Webster]
2. Artificial grotto-work.
[1913 Webster]