/ Thesaurus / U Synonyms of unnavigable Find synonyms for: Adjective1. unnavigable, impassable (vs. passable), unpassableusage: incapable of being navigatedWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language