The Collaborative International Dictionary of English v.0.48:
Monkish \Monk"ish\, a. Like a monk, or pertaining to monks; monastic; as, monkish manners; monkish dress; monkish solitude. -- Monk"ish*ness, n. [1913 Webster]WordNet (r) 3.0 (2006):
monkish adj 1: befitting a monk; inclined to self-denial