Section 8 is a category of discharge from the United States military, used for a servicemember judged mentally unfit for service. It also came to mean any servicemember given such a discharge or behaving as if deserving such a discharge, as in the expression, "he's a Section 8". The term comes from Section VIII of the World War II-era United States Army Regulation 615-360, which provided for the discharge of those deemed unfit for military service.
Discharge under Section 8 is no longer practiced, as medical discharges for psychological/psychiatric reasons are now covered by a number of regulations. In the Army, such discharges are handled under the provisions of AR 635-200, Active Duty Enlisted Administrative Separations. Chapter 5, paragraph 13 governs the separation of personnel medically diagnosed with a personality disorder.
Section 8 became a household phrase when used in the 1970s TV series M*A*S*H, in which the character Corporal Klinger was continually seeking one (until he eventually abandoned his efforts). Other pop culture references to the term include: