diminished capacity

noun | \ də-ˈmi-nisht- \ | di·min·ished capacity

1. : an abnormal mental condition that renders a person unable to form the specific intent necessary for the commission of a crime (as first-degree murder) but that does not amount to insanity — called also diminished responsibility, partial insanity; compare insanity, irresistible impulse test, m'naghten test, substantial capacity test

2. a : a defense based on a claim of diminished capacity

   b : the doctrine that diminished capacity may negate an element of a crime

   Note: If diminished capacity is shown, negating an element of the crime with which a defendant is charged, the defendant can only be convicted of a lesser offense that does not include the element.