1.not in good condition; damaged or decayed;
an unsound foundation
2.not sound financially;
unsound banking practices
3.containing or based on a fallacy;
fallacious reasoning
4.suffering from severe mental illness;
of unsound mind
5.physically unsound or diseased;
has a bad back
6.of e.g. advice
7.in deplorable condition;
a street of bedraggled tenements