I don't think even that's a sufficient definition.
It's that all observers (except psychos), no matter their own particular circumstances and characteristics, would assign approval/disapproval in exactly the same way.
Psychopaths are quite capable of perceiving objective truths. In fact if there was an objective morality I expect it would work better for psychopaths than for anyone else.
This is a thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. The previous thread is at close to 500 comments.