lu·na·tic / ˈloōnəˌtik/ • n. a mentally ill person (not in technical use). ∎  an extremely foolish or eccentric person: this lunatic just accelerated out of the side of the road.• adj. mentally ill (not in technical use). ∎  extremely foolish, eccentric, or absurd: he would be asked to acquiesce in some lunatic scheme.ORIGIN: Middle English: from Old French lunatique, from late Latin lunaticus, from Latin luna ‘moon’ (from the belief that changes of the moon caused intermittent insanity).

Lunatic ★ 1991

“Some minds should be wasted” according to the film promo and if you're in the mood for an amateur mind (and time) waster, this is for you. High schoolers in the woods encounter mayhem in the best horror tradition as the innocents are slaughtered by an escapee from the local lunatic asylum. 90m/C VHS . Rocky Tucker, Ondrea Tucker, Brian D'Lawrence, Keith Vallot, Bronwyn St. John, Cameron Derrick, Ernest Jackson, Rookie Macpherson, Susan Spain; D: James Tucker; W: James Tucker.

lunatic orig. affected with the kind of insanity that was supposed to depend on changes of the moon XIII; sb. XIV. — (O)F. lunatique — L. lūnāticus, f. lūna moon; see prec. -ATIC.
Hence lunacy XVI.

lu·na·tic fringe • n. an extreme or eccentric minority within society or a group.