/ Thesaurus / T Synonyms of thirty one Find synonyms for: Adjective1. thirty-one, 31, xxxi, cardinal (vs. ordinal)usage: being one more than thirtyWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language