Word Origin & History
O.E. ful "dirty, stinking, vile, corrupt," from P.Gmc. *fulaz (cf. O.H.G. fül, M.Du. voul, Ger. faul, Goth. füls), from base *fu-, corresponding to PIE *pu-, perhaps from the sound made in reaction to smelling something bad (cf. Skt. puyati "rots, stinks," putih "foul, rotten;" Gk. puon "discharge
from a sore;" L. pus "putrid matter," putere "to stink," putridus "rotten;" Lith. puviu "to rot"). Of weather, first recorded late 14c. In the sporting sense of "irregular, unfair" it is first attested 1797, though foul play is recorded from mid-15c. O.E. ful occasionally meant "ugly" (as contrasted with fæger (adj.), modern fair), a sense frequently found in M.E., and the cognate in Swed. is the usual word for "ugly." Foulmouthed first attested 1590s in Shakespeare. Foulmart was a M.E. word for "polecat" (from O.E. mearð "marten"). As a verb, it is from O.E. fulian. Related: Fouled; fouling.