/ Thesaurus / T Synonyms of twenty first Find synonyms for: Adjective1. twenty-first, 21st, ordinal (vs. cardinal)usage: coming next after the twentieth in positionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: ravenous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language