/ Thesaurus / C Synonyms of catastrophic illness Find synonyms for: Noun1. catastrophic illness, illness, unwellness, malady, sicknessusage: severe illness requiring prolonged hospitalization or recovery; usually involves high costs for hospitals and doctors and medicinesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: candid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language