/ Thesaurus / S Synonyms of sixty four Find synonyms for: Adjective1. sixty-four, 64, lxiv, cardinal (vs. ordinal)usage: being four more than sixtyWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language