Fool

c.1275, from O.Fr. fol “madman, insane person,” also an adj. meaning “mad, insane,” from L. follis “bellows, leather bag,” in V.L. used with a sense of “windbag, empty-headed person” (see follicle). Cf. also Skt. vatula- “insane,” lit. “windy, inflated with wind.”

Fowl

O.E. fugel “bird,” general Gmc. word (cf. Gothic fugls), from P.Gmc. *foglaz (cf. O.N. fugl, M.Du. voghel, Ger. vogel, Goth. fugls), probably by dissimilation from *flug-la-, lit. “flyer,” from the same root as O.E. fleogan, modern fly (v.1). Originally “bird;” narrower sense of “domestic hen or rooster” (the main modern meaning) is first recorded 1580; in U.S. also extended to ducks and geese.