LUNATIC


Meaning of LUNATIC in English

■ noun a person who is mentally ill (not in technical use).

↘an extremely foolish person.

Origin

ME: from OFr. lunatique , from late L. ~us , from L. luna 'moon' (from the belief that changes of the moon caused intermittent insanity).

Concise Oxford English vocab.      Сжатый оксфордский словарь английского языка.