clean 词源(Etymology) - 趣词词源[英文版]

clean [clean 词源字典]: clean: [OE] Etymologically, clean and German klein ‘small’ are the same word. Both go back to West Germanic *klainoz, which meant ‘clear, pure’, but whereas the English adjective has stayed fairly close to the original meaning, the German one has passed via ‘clean’, ‘neat’, ‘dainty’, and ‘delicate’ to ‘small’. It has been speculated that *klainiz was based on *klai-, which connoted ‘stickiness’ (it was the source of English clay and clammy).

The reasoning is that something sticky, perhaps from a coating of oil, would have been perceived as having a clear or shiny surface, and there may also have been a suggestion of the purity conferred by a ceremonial anointing with oil. The derivatives cleanse and cleanly (whence cleanliness) are both Old English formations.
=> clammy, clay, cleanse[clean etymology, clean origin, 英语词源]
clean (adj.): Old English clæne "free from dirt or filth; pure, chaste, innocent; open, in the open," of beasts, "ritually safe to eat," from West Germanic *klainoz "clear, pure" (cognates: Old Saxon kleni "dainty, delicate," Old Frisian klene "small," Old High German kleini "delicate, fine, small," German klein "small;" English preserves the original Germanic sense), from PIE root *gel- "bright, gleaming" (cognates: Greek glene "eyeball," Old Irish gel "bright").

"Largely replaced by clear, pure in the higher senses" [Weekley], but as a verb (mid-15c.) it has largely usurped what once belonged to cleanse. Meaning "whole, entire" is from c. 1300 (clean sweep in the figurative sense is from 1821). Sense of "innocent" is from c. 1300; that of "not lewd" is from 1867; that of "not carrying anything forbidden" is from 1938; that of "free of drug addiction" is from 1950s. To come clean "confess" is from 1919, American English.
clean (v.): mid-15c., "make clean," from clean (adj.). Related: Cleaned; cleaning. From clean out "clean by emptying" comes sense of "to leave bare" (1844); cleaned-out "left penniless by losses" is from 1812.
clean (adv.): Old English clæne "dirtlessly," also "clearly, fully, entirely;" see clean (adj.). Compare similar use of German rein "clean."