Added 9 October 2026 ill-defined adjective Categories: Describing WordsObscure Words adjective ! Definition from WordNet 3.1, Princeton University. More about ill-defined at Wordnik → Where our words come from → Poorly stated or described. he confuses the reader with ill-defined terms and concepts Origin From ill + defined. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: unclearblurryblurredhazyobscureelusiveambiguousequivocaluncertainvagueimpreciseinaccurate Back to today's word