Английский Этимологический словарь - shit (v.)

- O.E. scitan, from P.Gmc. *skit-, from PIE *skheid- "split, divide, separate." Related to shed (v.) on the notion of "separation" from the body (cf. L. excrementum, from excernere "to separate"). The noun is O.E. scitte "purging;" sense of "excrement" dates from 1585, from the verb. Extensive slang usage; meaning "to lie" is from 1934; that of "to disrespect" is from 1903; used for "obnoxious person" since at least 1508. Shat is a humorous past tense form, not etymological, from 18c. Shit-faced "drunk" is 1960s student slang; shit list is from 1942.