[Middle English moiste, from Old French, alteration (influenced by Latin musteus, juicy) of Vulgar Latin *muscidus, alteration of Latin mūcidus, moldy, from mūcus, mucus.] moist'ly adv., moist'ness n.
c.1374, from O.Fr. moiste "damp," from V.L. *muscidus "moldy," also "wet," from L. mucidus "slimy, moldy, musty," from mucus "slime" (see mucus). Alternate etymology is from L. musteus "fresh, green, new," lit. "like new wine," from musteum "new wine" (see must (n.1)). If this wasn't the source, it influenced the form of the other word in O.Fr. Moisture is attested from 1366.
Main Entry: moist Pronunciation: 'moist Function: adjective 1: slightly or moderately wet 2 a: marked by a discharge orexudation of liquid <moist eczema> b: suggestive of the presence of liquid —used of sounds heard in auscultation <moist rales>