When Christians talk about ‘subjective and objective morality,’ are they just spouting nonsense?

I think what the lesser folk mean when they spout this crap is that subjective morality is a moral code that can be kind of made up as you go, whereas objective morality is a moral code that rests on an unchanging moral foundation. Is this what they mean? If so, then can you see why I think it’s a load of crap? I mean, ‘objective morality’ rests on the unfounded belief that there is an unchanging moral foundation. There is no such thing, certainly not the bible from which people pick and choose morals. So the terms ‘subjective and objective morality’ are completely meaningless, right? Morality is a stand alone subject. What are the lesser folk trying to achieve by inventing meaningless terms like ‘subjective and objective morality’?