Violating the Ten Commandments, for example. Then there are the seven deadly sins (Pride, Envy, Wrath/Anger, Sloth, Avarice/Greed, Gluttony, and Lust).
An example of a moral absolute? Stealing would be immoral. Lying. Cheating. Not that I haven't done these things, mind you. But when I do, I feel bad about it. Some don't.
This is pretty basic stuff. Why do you ask?