Determinism is sometimes confused with fatalism. The difference is that determinism relies more on cause and effect when it comes to free will negation, while fatalism often claims that there is a predetermined destiny that is bound to happen regardless of us.
It is a theory that all human action is caused entirely by preceding events, and not by the exercise of the free will. In determinism, there is no free will because events happen because of previous events that happened. There is nothing that can influence that.
Compatibilism is often criticized as being just a form of soft determinism because they claim that free will can exist in the domain of determinism. Their critics often point out that compatibilism is very deterministic but that they avoid that term due to linguistic problems and that in essence there is no difference
Compatiblisim defines free will as capable of existing alongside determinism since free will can be found in things that are not metaphysical. If you make daily decisions on what food to eat then there's free will, but metaphysical things lack these.
