“Tough tiddy” (often spelled “tough titty”) is an old-school American slang phrase that means “tough luck”. It is used to tell someone that they just have to accept a bad situation because nothing can be done to change it. The phrase functions as a blunt, unsympathetic dismissal. Variants include “tough tit,” “tough tits,” or “hard titty”. A highly popular, rhyming extension of the phrase used primarily in American folklore and regional dialects is: “Tough titty said the kitty when the milk went dry.”

The noun “titty” or “tiddy” historically refers to a teat or breast. The phrase draws on the imagery of a nursing infant or animal encountering a dry or hard teat, resulting in an unfortunate lack of milk or comfort. While dictionaries like the Chambers Slang Dictionary trace its widespread use back to the 1920s, print archives show it is much older. The earliest recorded use of “tough titty” appears in an 1888 edition of the Bristol Courier in Tennessee. The variant “tough tiddy” was spotted shortly after in an 1894 edition of The Lowell Daily Sun in Massachusetts to describe a bowling team’s unfortunate loss.