Grammarist

Non compos mentis is a borrowed phrase or loan phrase. We will look at the definition of the term bon vivant, where it came from, and some examples of its use in sentences. Non compos mentis means mentally incompetent, insane, not in one’s right mind. The term is often used when mounting an insanity defense that will determine whether a defendant is found not guilty due to insanity in a criminal trial, in a hearing that will determine whether the defendant.