Lunatic is an informal term referring to a person who is considered as 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. Wikipedia
Lunatic:
Lunatic is an informal term referring to a person who is considered as 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. Wikipedia