/ Thesaurus / I Synonyms of ill defined Find synonyms for: Adjective1. ill-defined (vs. well-defined), unclearusage: poorly stated or described; "he confuses the reader with ill-defined terms and concepts"WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language