of sound mind

adjective

1. a : free from injury or disease : exhibiting normal health

   b : legally valid a sound title

2. a : free from error, fallacy, or misapprehension based on sound judicial reasoning

   b : legally valid a sound title

3. : showing good judgment or sense

intransitive verb

1. : to be based or founded : have a specified basis for an action —used with in those remedies for rent which sounded in contract —O. W. Holmes, Jr.