Loony

Loony

Adjective / Noun · /ˈluː.ni/

Definition

(Adjective, informal) mad, crazy, extremely foolish; (Noun, informal) a mad or eccentric person. Offensive when used to dismiss mental illness.

Origin

From lunatic (from Latin lunaticus — moonstruck, from luna — the moon) shortened through lunatic to loony. The belief that the moon caused madness was widespread in antiquity and persisted into modern times. Loony is attested from the mid-19th century as an informal shortening. Loony bin (a psychiatric hospital) follows naturally from the noun sense.