/ Thesaurus / M Synonyms of mission impossible Find synonyms for: Noun1. mission impossible, mission, charge, commissionusage: an extremely dangerous or difficult missionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language