Definition of unsound:
daft, dotty, tough, cuckoo, precarious, bananas, non compos mentis, moonstruck, big, fallacious, wacky, tumble-down, specious, fraudulent, screwy, incorrect, dilapidated, fruity, nutty, insecure, rotten, invalid, mentally ill, batty, maniac, high-risk, maniacal, disordered, cracked, mistaken, risky, decrepit, spoiled, bonkers, nuts, undependable, unwise, delicate, regretful, forged, sorry, puny, correct, corroded, unbalanced, demented, sane, flimsy, weakly, distraught, uncollectible, spoilt, ramshackle, sophistic, broken-down, false, spurious, inaccurate, lunatic, weak, strong, erroneous, indiscreet, ill-considered, fragile, unreliable, infirm, wise, bad, loco, unfit, imprudent, daffy, unstable, crazy, touched, tatterdemalion, loony, insane, wildcat, illogical, deceitful, bedraggled, speculative, rotted, crackers, untrue, off, damaged, unsubstantial, fluid, decayed, brainsick, long, injudicious, buggy, weak, mad, true, feeble, frail, insubstantial, impolitic, ill-advised, gaga, unhealthy.
- bad (part of speech: adjective)
- false (part of speech: adjective)
- "Jewish Fairy Tales and Legends", Gertrude Landa.
- "Life of Charles Dickens", Frank Marzials.
- "The Country Doctor", Honore de Balzac.