[1] : The Collaborative International Dictionary of English v.0.48

unsound \unsound"\, a.
   not sound; not whole; not solid; defective; infirm; diseased.
   1913 webster -- unsound"ly, adv. -- unsound"ness, n.
   1913 webster
see also:
unsound"ly unsound"ness 

[2] : WordNet (r) 2.0

unsound
     adj 1: not in good condition; damaged or decayed; "an unsound
            foundation" ant: sound
     2: not sound financially; "unsound banking practices" ant: sound
     3: containing or based on a fallacy; "fallacious reasoning";
        "an unsound argument" syn: fallacious
     4: suffering from severe mental illness; "of unsound mind"
        syn: mentally ill, unstable
     5: physically unsound or diseased; "has a bad back"; "a bad
        heart"; "bad teeth"; "an unsound limb"; "unsound teeth"
        syn: bad, unfit
     6: of e.g. advice
     7: in deplorable condition; "a street of bedraggled tenements";
        "a broken-down fence"; "a ramshackle old pier"; "a
        tumble-down shack" syn: bedraggled, broken-down, dilapidated,
         ramshackle, tatterdemalion, tumble-down
see also:
sound fallacious mentally ill unstable bad unfit 
bedraggled broken-down dilapidated ramshackle tatterdemalion 
tumble-down 

[3] : Moby Thesaurus II by Grady Ward, 1.0

267 moby thesaurus words for "unsound":
   albigensian, arian, catharist, donatist, ebionitist, erastian,
   gnostic, jansenist, jansenistic, jovinianist, jovinianistic,
   lollard, manichaean, monophysite, monophysitic, montanist,
   montanistic, pelagian, sabellian, waldensian, wyclifite, abnormal,
   adulterated, afflicted, ailing, antinomian, apocryphal, batty,
   bereft of reason, blemished, brainsick, broken-down, cachectic,
   chancy, crackbrained, cracked, crazed, crazy, crumbling, daft,
   damaged, dangerous, debilitated, decayed, decrepit, defective,
   deficient, delicate, deluded, demented, deprived of reason,
   deranged, desultory, dilapidated, diseased, disintegrating,
   disoriented, distraught, doubtful, drained, dubious, emanationist,
   enervated, erroneous, exhausted, failing, fallacious, fallible,
   faulty, feeble, flawed, flighty, flimsy, found wanting, fragile,
   frail, groundless, hairy, hallucinated, hazardous, healthless,
   heretical, heterodox, hylotheist, hylotheistic, ill, ill-advised,
   ill-considered, ill-contrived, ill-devised, ill-gauged, ill-judged,
   illogical, immature, impaired, imperfect, impolitic, imprecise,
   imprudent, impure, in poor health, inaccurate, inadequate,
   inadvisable, incomplete, inconclusive, inconsiderate, incorrect,
   indebted, indiscreet, inexact, inexpedient, infirm, injudicious,
   injured, insane, insecure, insensate, insolvent, insubstantial,
   invalid, irrational, jeopardous, lacking, languishing, loco,
   lunatic, mad, maddened, makeshift, manic, mazed, mediocre, mental,
   mentally deficient, meshuggah, mindless, misadvised, misguided,
   mixed, moon-struck, morbid, moribund, myopic, non compos,
   non compos mentis, nonorthodox, not all there, not perfect,
   not right, odd, of unsound mind, off, pale, pantheist, pantheistic,
   partial, patchy, pathological, peaked, peaky, perilous, poor,
   poorish, precarious, provisional, psycho, psychotic, queer,
   ramshackle, reasonless, reckless, reduced, reduced in health,
   rickety, risky, rocky, rotten, rotten at, run-down, senseless,
   shaky, shifting, shifty, short, shortsighted, sick, sickly,
   sketchy, slippery, specious, stark-mad, stark-staring mad, strange,
   temporary, tentative, tetched, thoughtless, ticklish, tottering,
   tottery, touched, treacherous, unaccepted, unadvised, unapproved,
   unauthentic, unauthoritative, unbalanced, uncanonical, uncertain,
   unconsidered, undependable, undeveloped, undiscerning, uneven,
   unfaithworthy, unfinished, unfirm, unforeseeing, unfounded,
   unhealthy, unhinged, unorthodox, unperfected, unpredictable,
   unproved, unreasonable, unreflecting, unreflective, unreliable,
   unrigorous, unsafe, unsane, unscriptural, unseeing, unsensible,
   unsettled, unsolid, unstable, unsteadfast, unsteady, unsturdy,
   unsubstantial, unsure, unsustained, untenable, unthinking,
   unthorough, unthoughtful, untrue, untrustworthy, unwell,
   unwholesome, unwise, valetudinarian, valetudinary, wandering, weak,
   weakened, weakly, wicked, with low resistance, witless, wobbly,
   wounded, wrong

Unsound >> U Words
Unsound, definition of term: Unsound
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