WordRel.com

• not sound financially

  antonym	sound
  derivation	unsoundness
  also	brokendamagedinjuredunfitunhealthyunwholesome
  similar	badhigh-risklongriskyspeculativewildcat

• not in good condition; damaged or decayed

  antonym	sound
  derivation	unsoundness
  similar	corrodeddecayedrottedrotten

• suffering from severe mental illness

  synonym	mentally illunstable
  derivation	unsoundness
  similar	insane

• containing or based on a fallacy

  synonym	fallacious
  derivation	unsoundness
  similar	invalid

• physically unsound or diseased

  synonym	badunfit
  derivation	unsoundness
  similar	unhealthy

• of e.g. advice

  similar

  undependableunreliable