late Old English clænsunge "a cleansing, a purifying, castigation; chastity, purity," verbal noun from the root of cleanse. As a present-participle adjective, attested from c. 1300.
late 14c., "thing that cleanses" (usually figurative, in reference to purging sin), also "a purgative medicine;" 1560s in a literal sense "one who or that which makes clean;" agent noun from cleanse (v.). Old English had clænsere "priest."
Old English clæne "free from dirt or filth, unmixed with foreign or extraneous matter; morally pure, chaste, innocent; open, in the open," of beasts, "not forbidden by ceremonial law to eat," from West Germanic *klainja- "clear, pure" (source also of 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), perhaps from PIE root *gel- "bright, gleaming" (source also of Greek glene "eyeball," Old Irish gel "bright"). But Boutkan doubts the IE etymology and that the "clean" word and the "small" word are the same.
"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 "not lewd" (as in good, clean fun) 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.
"to cleanse, clear away foul or offensive matter from," 1620s, from French déterger (16c.), from Latin detergere "to wipe away, cleanse," from de "off, away" (see de-) + tergere "to rub, polish, wipe," which is of uncertain origin. Related: Deterged; deterging.
c. 1300, purgen, "clear of a charge or suspicion," from Anglo-French purger, Old French purgier "wash, clean; refine, purify" morally or physically (12c., Modern French purger) and directly from Latin purgare "cleanse, make clean; purify," especially in reference to the body, "free from what is superfluous; remove, clear away," but also figuratively "refute, justify, vindicate," from Old Latin purigare, from purus "pure" (see pure) + root of agere "to set in motion, drive; to do, perform" (from PIE root *ag- "to drive, draw out or forth, move").
By mid-14c. as "to cleanse (a person or soul) from sin or moral defilement; to cleanse, clear, purify" (metal, etc.), also medicinally "to cleanse the body or digestive tract by a laxative, diuretic, or emetic." The figurative sense of "make ideal or pure, rid of objectionable elements or members" is by 1580s. Related: Purged; purging. The Latin verb is also the source of Spanish purgar, Italian purgare.
"cleansing, purging," 1610s, from Latin detergentem (nominative detergens), present participle of detergere "to wipe away, cleanse," from de "off, away" (see de-) + tergere "to rub, polish, wipe," which is of uncertain origin. Originally a medical term.
Old English wipian "to wipe, cleanse," from Proto-Germanic *wipjan "to move back and forth" (source also of Danish vippe, Middle Dutch, Dutch vippen, Old High German wifan "to swing"), from PIE root *weip- "to turn, vacillate, tremble."