The Collaborative International Dictionary of English v.0.48:

Fust \Fust\ (f[u^]st), n. [OF. fust, F. f[^u]t, fr. L. fustis
   stick staff.] (Arch.)
   The shaft of a column, or trunk of a pilaster. --Gwilt.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fust \Fust\, n. [OF. fust cask, F. f[^u]t cask, taste or smell
   of the cask, fustiness, cf. sentir le f[^u]t to taste of the
   cask. See 1st Fust.]
   A strong, musty smell; mustiness.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fust \Fust\, v. i.
   To become moldy; to smell ill. [Obs.]
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "fust":
   age, antiquate, become extinct, become obsolete, date, fade,
   fossilize, grow old, hang fire, idle, lose currency, molder,
   obsolesce, outdate, perish, rust, sleep, slumber, smolder,
   stagnate, superannuate, vegetate