implacable

Merriam-Webster's Word of the Day for September 15, 2016 is: implacable • \im-PLAK-uh-bul\  • adjective : not placable : not capable of being appeased, significantly changed, or mitigated Examples: "I am studying physics at a small graduate school because the implacable laws of the universe are of interest to me." — Fiona Maazel, Ploughshares, Summer 2015 "Through his audacity, his vision, and his implacable faith in his future success, Philip Michael Thomas can say that he gave the most accomplished artists in history something to strive for." — Sophie Gilbert, The Atlantic, 9 June 2016 Did you know? Implacable is based on the Latin verb placare, meaning "to calm" or "to soothe." It joins the negative im- to the root to describe something that cannot be calmed or soothed or altered. The root placare also gave us placate. You may ask, what about the similar-looking words placid and placebo? These words are related to implacable and placate, but not as closely as you might suspect. They come from the Latin verb placēre, a relative of placare that means "to please." See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.