1570s, "to corrupt, contaminate," also "to touch, tinge, imbue slightly" (1590s), from Middle English teynten "to convict, prove guilty" (late 14c.), which is partly from Old French ataint, past participle of ataindre "to touch upon, seize" (see attainder). It also is from Anglo-French teinter "to color, dye" (early 15c.), from Old French teint (12c.), past participle of teindre "to dye, color," from Latin tingere (see tincture). Related: Tainted; tainting.
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.