10 U.S.C. § 1141: Involuntary separation defined

in the case of a regular officer (other than a retired officer), the officer is involuntarily discharged under other than adverse conditions, as characterized by the Secretary concerned; in the case of a reserve officer who is on the active-duty list or, if not on the active-duty list, is on full-time active duty (or in the case of a member of the National Guard, full-time National Guard duty) for the purpose of organizing, administering, recruiting, instructing, or training the reserve components, the officer is involuntarily discharged or released from active duty or full-time National Guard (other than a release from active duty or full-time National Guard duty incident to a transfer to retired status) under other than adverse conditions, as characterized by the Secretary concerned; in the case of a regular enlisted member serving on active duty, the member is (A) denied reenlistment, or (B) involuntarily discharged under other than adverse conditions, as characterized by the Secretary concerned; in the case of a reserve enlisted member who is on full-time active duty (or in the case of a member of the National Guard, full-time National Guard duty) for the purpose of organizing, administering, recruiting, instructing, or training the reserve components, the member (A) is denied reenlistment, or (B) is involuntarily discharged or released from active duty (or full-time National Guard) under other than adverse conditions, as characterized by the Secretary concerned; in the case of an officer of the Space Force (other than a retired officer), the officer is involuntarily discharged or released from active duty under other than adverse conditions, as characterized by the Secretary of the Air Force; and denied reenlistment; or involuntarily discharged or released from active duty under other than adverse conditions, as characterized by the Secretary of the Air Force.