A jock is either a person who finds identity in sports or who finds their acceptance amongst those who do.
They are by no means inferior or, for that matter, superior however are often seen that way by minority groups. They may appear inferior because they are interested/preoccupied with things that require low intelligence, however they may still be intelligent and just content to not exercise it all day long. They are also sometimes seen as superior because they are very self-confident and often physically strong/built (which sometimes makes them attractive to the opposite gender). This is a direct result of either wanting to improve their sporting ability or wanting to fit in with people of high sporting ability.
Unlike athletes, for jocks sport is not an activity but a status symbol, when their team/player achieves success they see it as a personal achievement. Athletes may or may not be jocks.
*Note: Often people who are highly intelligent (and who like to exercise their intelligence) look down upon jocks for being so interested in unintellectual things, they have reason to feel superior but this is no excuse for being prejudiced (as applies to jocks towards them).
The jocks are watching soccer at my house tonight so can i come play guitar at yours?
Don't be such a jock, it's only a game.
The jocks are going to be grumpy today, our team lost badly last night.