desaturate (v.)

active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.

As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.

1530s, "to satisfy, satiate, fill full" (senses now obsolete), from Latin saturatus, past participle of saturare "to fill full, sate, drench," from satur "sated, full" (from PIE root *sa- "to satisfy").

In chemistry, the meaning "to impregnate or unite with until no more can be received" is from 1680s; the general sense of "soak thoroughly, imbue (with)" is by 1756. The commercial sense of "oversupply" (a market, with a product) is by 1958. As a noun, "a saturated fat," by 1959. Related: Saturated; saturating.