" Cry wolf "
Intentionally raise a false alarm.
Now Billy, there's no point crying wolf just to stay up a bit later. We all know that there are no witches in your bedroom.
Where did it originate?:
From the 'Shepherd Boy who cried Wolf' story in Aesop's Fables, translated into English in the 17th century.
Where is it used?:
Hear the idiom spoken: