/ Thesaurus / F Synonyms of flame retardant Find synonyms for: Adjective1. flameproof, flame-retardant, noncombustible (vs. combustible), incombustibleusage: resistant to catching fireWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: grimace Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language