smiteyoudaoicibaDictYouDict[smite 词源字典]
smite: [OE] Old English smītan meant ‘smear’ (it came from a prehistoric Germanic *smītan, which also produced German schmeissen ‘throw’, and probably went back ultimately to the Indo-European base *smēi-, source of Greek smékhein ‘rub, cleanse’, from which English gets smegma [19]). Exactly the same odd semantic development from ‘smear’ to ‘hit’, presumably via an intervening ‘stroke’, happened in the case of strike.
=> smegma, smut[smite etymology, smite origin, 英语词源]
smite (v.)youdaoicibaDictYouDict
"to hit, strike, beat," mid-12c., from Old English smitan, which however is attested only as "to daub, smear on; soil, pollute, blemish, defile" (strong verb, past tense smat, past participle smiten), from Proto-Germanic *smitan (cognates: Swedish smita, Danish smide "to smear, fling," Old Frisian smita, Middle Low German and Middle Dutch smiten "to cast, fling," Dutch smijten "to throw," Old High German smizan "to rub, strike," German schmeißen "to cast, fling," Gothic bismeitan "to spread, smear"). "The development of the various senses is not quite clear, but that of throwing is perh. the original one" [OED]. Watkins suggests "the semantic channel may have been slapping mud on walls in wattle and daub construction" and connects it with PIE *sme- "to smear;" Klein's sources also say this.

Sense of "slay in combat" (c. 1300) is from Biblical expression smite to death, first attested c. 1200. Meaning "visit disastrously" is mid-12c., also Biblical. Meaning "strike with passion or emotion" is from c. 1300.