/ Thesaurus / U Synonyms of unappeasable Find synonyms for: Adjective1. grim, inexorable, relentless, stern, unappeasable, unforgiving, unrelenting, implacable (vs. placable)usage: not to be placated or appeased or moved by entreaty; "grim determination"; "grim necessity"; "Russia's final hour, it seemed, approached with inexorable certainty"; "relentless persecution"; "the stern demands of parenthood"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language