[ uhn-sound ]
/ ʌnˈsaʊnd /

adjective, un·sound·er, un·sound·est.

not sound; unhealthy, diseased, or disordered, as the body or mind.
decayed or impaired, as timber or foods; defective.
not solid or firm, as foundations.
not well-founded or valid; fallacious: an unsound argument.
easily broken; light: unsound slumber.
not financially strong; unreliable: an unsound corporation.

Origin of unsound

Middle English word dating back to 1275–1325; see origin at un-1, sound2
Related formsun·sound·ly, adverbun·sound·ness, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for unsound

British Dictionary definitions for unsound


/ (ʌnˈsaʊnd) /


diseased, weak, or unstableof unsound mind
unreliable or fallaciousunsound advice
lacking solidity, strength, or firmnessunsound foundations
of doubtful financial or commercial viabilityan unsound enterprise
(of fruit, timber, etc) not in an edible or usable condition
Derived Formsunsoundly, adverbunsoundness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unsound



early 14c., of persons, "diseased, wounded," from un- (1) "not" + sound (adj.). Cf. Middle Low German unsund, Middle Dutch ongesont, German ungesund. Meaning "morally corrupt" is recorded from c.1300; that of "not mentally healthy" is from 1540s. Sense of "not based on reasoning or fact" is attested from 1590s.

Online Etymology Dictionary, © 2010 Douglas Harper