If you refer to someone as an overlord, you mean that they have great power and are likely to use it in a bad way. We really don't want to be the overlords of the Palestinian population The running of Welsh rugby was left in chaos yesterday after a vote of no confidence in the game's overlords
In former times, an overlord was someone who had power over many people. Henry II was the first king to be recognized as overlord of Ireland. someone with great power over a large number of people, especially in the past