MUSTY
fusty, musty, frowsty
(adjective) stale and unclean smelling
moldy, mouldy, musty
(adjective) covered with or smelling of mold; “moldy bread”; “a moldy (or musty) odor”
Source: WordNet® 3.1
Etymology
Adjective
musty (comparative mustier, superlative mustiest)
Having a stale odor.
Source: Wiktionary
Mus"ty, a. [Compar. Mustier; superl. Mustiest.] Etym: [From L. mustum
must; or perh. fr. E. moist. Cf. Must, n., Moist.]
1. Having the rank, pungent, offencive odor and taste which
substances of organic origin acquire during warm, moist weather; foul
or sour and fetid; moldy; as, musty corn; musty books. Harvey.
2. Spoiled by age; rank; stale.
The proverb is somewhat musty. Shak.
3. Dull; heavy; spiritless. "That he may not grow musty and unfit for
conversation." Addison.
Source: Webster’s Unabridged Dictionary 1913 Edition