/ Thesaurus / D Synonyms of dimetapp Find synonyms for: Noun1. Dimetapp, antihistamine, nasal decongestantusage: trade name for a drug containing an antihistamine and a decongestant; used to relieve nasal congestion and to treat rhinitisWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: frowzy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language