implacable

Merriam-Webster's Word of the Day for July 13, 2026 is:

implacable • \im-PLAK-uh-bul\  • adjective

Someone or something described as implacable is not capable of being appeased or changed.

// The project faced implacable resistance from community members, and is now off the table.

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Examples:

“Unlike, say, the globetrotting stories of Ian Fleming or John le Carré, in which victories only temporarily frustrate an implacable foe, [Agatha] Christie’s smaller worlds feel put right when the cover closes or credits roll.” — The Economist, 17 Jan. 2026

Did you know?

Implacable is rooted in the Latin verb placare, meaning “to soothe,” but its im- prefix is a variant of the negating prefix in- (as in inactive) and it signals that there’s nothing warm and fuzzy here. Someone or something described as implacable cannot be soothed, which usually means trouble: implacable is most often attached to words like foe, enemy, hatred and hostility. The opposite of implacable is, of course, placable; it means “easily soothed,” but sadly isn’t called upon very often. Another placare word is likely more familiar. Placate means “to soothe or appease”; it’s frequently applied when an angry person is made to feel less so.