A magical spell or power that causes someone to have a difficult or unpleasant time. (Cambridge Dictionary)
Whammy is used in expressions such as double whammy and triple whammy to indicate that two or three unpleasant or difficult situations occur at the same time, or occur one after the other. (Collins Dictionary)
An event with a powerful and unpleasant effect; a blow. (Oxford Dictionaries)
A supernatural power bringing bad luck. (Merriam – Webster)
Example
There’s a Whammy for that. img flip.
