Retribute is a verb meaning to pay back, it could mean this in a revenge way or a nice way. In retribution, it would be taken as the revenge way since retribution somewhat goes down the punishment road. An example of retribution in a sentence is, "This includes altering it and redistributing, without fear of retribution from a ' copyright ' holder." This means that this person has included somewhere that they have changed this certain picture or video so that they would not be punished by having their picture or video taken down.
The suffix -tion means an act or state of something, in retribution it would be taken as the act of paying back or in a way we could understand it would be known as punishing. Though, since it is the act of punishing or paying back, it would be known as a punishment. This is what the overall noun retribution means, a punishment that is put upon someone who has done a crime or something wrong. Just to briefly explain how 're' in retribute means, the prefix 're' means back or again. Tribute means an act or statement, so when you put those two together you get the act of doing something again or getting back at someone or something.