adjective

1. in or of a style of painting, sculpture, etc. in which forms of persons and animals are intermingled as with foliage, flowers, or fruits in a fantastic or bizarre design
2. characterized by distortions or striking incongruities in appearance, shape, or manner; fantastic; bizarre
3. ludicrously eccentric or strange; ridiculous; absurd

Etymology: Fr < It grottesca (pittura), orig., (picture) in a cave < grotta, grotto: from resemblance to designs found in Roman caves

noun

1. a grotesque painting, sculpture, design, etc.
2. a grotesque thing or quality