"stale-smelling," late 14c., from French fusté "fusty, tasting of the cask," from Old French fuste, fuist "wine cask," originally "stick, stave, wood" (Modern French fût), from Latin fustis "staff, stick of wood" (see fustigate). Related: Fustiness. Fustilugs was 17c. slang for "a woman of gross or corpulent habit" [OED], later generally in dialect for a big-boned person.