adjective, frowst·i·er, frowst·i·est. British Informal.
- musty; ill-smelling.
adjective -stier or -stiest
- ill-smelling; stale; musty
“having an unpleasant smell,” 1865, of unknown origin; perhaps related to Old French frouste “ruinous, decayed,” or to Old English þroh “rancid;” both of which also are of uncertain origin.