Over 200 literary terms, Shmooped to perfection.
The protagonist is the one we root for in the novel—the character whose life we're most concerned with or whose inner life we're given access to. A protagonist is often opposed by an antagonist of some sort, who keeps our main character in conflict until he triumphs over it. Or not.
A protagonist doesn't always wear a white hat, and he doesn't always fight a dude wearing a black one. The best protagonists are often the most complex—sometimes kind, sometimes loathsome, always engaging.
Shmoop's personal favorite? Yossarian, hands down.