- "Loony" redirects here. For the Canadian 1 dollar coin (loonie), see Canadian 1 dollar coin. Or see Looney or Luni.
Lunatic is an informal term referring to a person who is considered
mentally ill,
dangerous,
foolish or unpredictable, conditions once attributed to
lunacy. The term may be considered insulting in serious contexts in modern times, but is now more likely to be used in friendly jest. The word derives from
lunaticus meaning "of the moon" or "moonstruck". The term was once commonly used in law.
