Online Dictionary

fly (n.) Explained

fly (n.) at English => English (English Etymology) Of Explained:

O.E. fleoge, from P.Gmc. *fleugjon (cf. O.S. fleiga, O.N. fluga, M.Du. vlieghe, Ger. Fliege "fly); lit. "the flying (insect)" (cf. O.E. fleogende "flying"), from same source as fly (v.1). Originally "any winged insect" (hence butterfly, etc.); long used by farmers and gardeners for any insect parasite. Slang adj. meaning "clever, alert" first recorded 1811 may be from the notion of the insect being hard to catch (other theories trace it to fledge or flash); 1990s use may be a revival or a reinvention. Fly on the wall "unseen observer" first recorded 1949. An O.E. word for "curtain" was fleonet "fly-net." ///