Moral relativism

A forbidden term.

In the antiquated sense, moral relativism is the belief that morality is in the eye of the beholder. This makes it a tad difficult to explain why it is immoral to impose one's morality on someone else. It also makes it a tad inconvenient for governments (or, more generally, social elites), which are in the business of imposing some morality on everyone, or different moralities on different constituencies, whichever is more politically convenient or necessary.