To beat a dead horse means to keep talking about a problem or trying to change something even though nothing more can be done. It describes wasting time and effort on something that is already finished or decided.
The idiom dates back to the time before cars, when horses were used to move things around. It comes from the image of a working horse that has already died and cannot move anymore. Hitting it would not make it work again, so the effort would be pointless.
The idiom dates back to the time before cars, when horses were used to move things around. It comes from the image of a working horse that has already died and cannot move anymore. Hitting it would not make it work again, so the effort would be pointless.
We've already decided on the plan, so there's no point beating a dead horse.