beat a dead horse—(also: flog a dead horse) pursue a futile goal; try to revive interest in a dead issue:
- Son, we talked about this and the decision was “no.” You are beating a dead horse.
work off the dead horse—(also: work out the dead horse) do work for which payment has already been made:
- The sailor was advanced one month’s pay…. During the first month out, he was “working off the dead horse.”