The Collaborative International Dictionary of English v.0.48:
Prankish \Prank"ish\, a. Full of pranks; frolicsome. [1913 Webster]WordNet (r) 3.0 (2006):
prankish adj 1: naughtily or annoyingly playful; "teasing and worrying with impish laughter"; "a wicked prank" [syn: arch, impish, implike, mischievous, pixilated, prankish, puckish, wicked]