unsound
adj.
not in good condition; damaged or decayed
an unsound foundation
adj.
not sound financially
unsound banking practices
adj.
containing or based on a fallacy
fallacious reasoning|an unsound argument
Synonym: fallacious
adj.
suffering from severe mental illness
of unsound mind
adj.
physically unsound or diseased
has a bad back|a bad heart|bad teeth|an unsound limb|unsound teeth
Synonym: bad, unfit
adj.
of e.g. advice
Antonym: sound