/ Thesaurus / G Synonyms of gustavus i Find synonyms for: Noun1. Gustavus, Gustavus Iusage: king of Sweden who established Lutheranism as the state religion (1496-1560)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language