1. (

• unsound ,

) not in good condition; damaged or decayed; "an unsound foundation" ;

2. (

• unsound

) not sound financially; "unsound banking practices" ;

3. (

• fallacious ,
• unsound

) containing or based on a fallacy; "fallacious reasoning"; "an unsound argument" ;

4. (

• mentally_ill ,
• unsound ,
• unstable

) suffering from severe mental illness; "of unsound mind" ;

5. (

• bad ,
• unfit ,
• unsound

) physically unsound or diseased; "has a bad back"; "a bad heart"; "bad teeth"; "an unsound limb"; "unsound teeth" ;

6. (

• unsound

) of e.g. advice ;