/ Thesaurus / M Synonyms of mental unsoundness Find synonyms for: Noun1. derangement, mental unsoundness, unbalance, insanityusage: a state of mental disturbance and disorientationWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: jugular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language