7 letters · 9 points in Scrabble
noun an insane person
noun a reckless impetuous irresponsible person
adjective insane and believed to be affected by the phases of the moon
originFrom Middle English lunatik, from Old French lunatique, from Late Latin lunaticus (“moonstruck”), derived from Latin luna (“moon”), the connection stemming from the belief that changes of the moon caused intermittent insanity.
Etymology from Wiktionary, CC BY-SA 3.0