be of unsound mind

be of unsound mind

To have impaired or dysfunctional thought, memory, and/or cognitive understanding; unable to think and/or understand for oneself. My poor grandfather has been of unsound mind ever since he suffered that stroke last year.
See also: mind, of, unsound
References in periodicals archive ?
Attempts are made to disparage me so badly that I am made out to be of unsound mind.