detergent (adj.)

"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.

"detergent substance," 1670s, from detergent (adj.). Originally a medical term; application to "chemical cleansing product" is by 1932.