A cooperative game is any game that you play cooperatively with others instead of opposed to other players. Massive Online Roleplaying games, some tabletop games, Pen and Paper Roleplaying games, and certain video games all fit into this category.
All of them require that you play well with others, but that’s not as easy as it sounds.
**Disclaimer: This is my opinion and I have almost no experience playing MMO-RPGs.**