Synonyms for confirm Found 6 synonyms across 2 meanings for “confirm”. establish or strengthen as with new evidence or facts (verb) corroboratesustainsubstantiatesupportaffirm strengthen or make more firm (verb) reassert Explore Related Words Rhymes with confirmSynonyms for corroborateSynonyms for sustainSynonyms for substantiateSynonyms for supportSynonyms for affirm Synonym Finder | Rhyme Finder | Poetry Editor