/ Thesaurus / F Synonyms of flatly Find synonyms for: Adverb1. flatly, categorically, unconditionallyusage: in an unqualified manner; "he flatly denied the charges"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language