Guys, you may not realize it, but when you hang out with your buds, you fraternize; that is, you associate in a friendly fashion with other men as though they were your brothers.
As your wives or girlfriends would be quick to tell you, there's an undercurrent of misbehavior to the term fraternize. At its most harmless, it means a kind of wild frat house behavior (frat or fraternity also coming from the Latin term fraternus, meaning "brotherly."). At its worst, there's an implication of illegality or skullduggery, as in the common phrase "fraternizing with the enemy." So party on, but don't be a traitor.