More about slake
Slake means “to lessen or allay something by satisfying it.” While we can slake our curiosity, desire, hunger, or anger, we most commonly say we slake our thirst. Slake comes from Middle English slaken “to mitigate, allay, moderate, lessen one’s efforts,” from Old English slacian “to slacken.” Old English slacian is a verb based off the adjective sleac, slæc, variously meaning “loose, lazy, careless, sluggish, lax (of conduct),” which by Middle English (as slac, slak) narrowed to the sense of “loose, not tight,” the principal sense of its modern form, slack, today. Old English sleac (via Germanic slak-) derives from the Proto-Indo-European root (s)lēg-, which, in its Latin variants, ultimately yielded such English words as languid, languish, lax, lease, release, and relax. Once again, etymology offers an important life lesson: it’s best not to languish, so slake your thirst—with a beverage of your choice—and relax, but don’t be too lax about it and slack off.