: affected by or as if by the moon: such as. a : mentally unbalanced.

What does it mean to be Moon Struck?

Moonstruck literally means to be affected by the moon, but moonstruck people are dreamy and in love. You can use the adjective moonstruck to mean "insane" or "loony" in general, but it's most often connected to the idea of being lovesick or romantic and irrational.

How can you explain the term lunatic?

Lunatic is an antiquated term referring to a person who is seen as mentally ill, dangerous, foolish, or crazy—conditions once attributed to "lunacy". The word derives from lunaticus meaning "of the moon" or "moonstruck".