/ Thesaurus / U Synonyms of underseal Find synonyms for: Noun1. undercoat, underseal, sealusage: seal consisting of a coating of a tar or rubberlike material on the underside of a motor vehicle to retard corrosionWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: philanthropy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language