Flogging a dead horse

Flogging a dead horse (alternatively beating a dead horse, or beating a dead dog in some parts of the Anglophone world) is an idiom that means to continue a particular endeavour is a waste of time as the outcome is already decided.

Flogging a dead horse

Flogging a dead horse (alternatively beating a dead horse, or beating a dead dog in some parts of the Anglophone world) is an idiom that means to continue a particular endeavour is a waste of time as the outcome is already decided.