Synonyms for Grotesque (same or very similar meaning)
WordNet sense 1 (ludicrously odd):
antic, fantastic, fantasticalWordNet sense 2 (being definitely out of the ordinary and unexpected; slightly odd or even a bit weird):
strange, unusualWordNet sense 3 (distorted and unnatural in shape or size; abnormal and hideous):
monstrous, unnaturalFrom the ODE community, based on WordNetadd/edit