The Collaborative International Dictionary of English v.0.48:
Coltish \Colt"ish\, a. Like a colt; wanton; frisky. [1913 Webster] He was all coltish, full of ragery. --Chaucer. -- Colt"ish*ly, adv. -- Colt"ish*ness, n. [1913 Webster]WordNet (r) 3.0 (2006):
coltish adj 1: given to merry frolicking; "frolicsome students celebrated their graduation with parties and practical jokes" [syn: coltish, frolicsome, frolicky, rollicking, sportive]