The Unarmed slot is the very basic weapon - this means using your fists to bring on the fight. This is a permanent slot, and cannot be lost in any way.
Your fists are obviously used in closed quarters. If you manage to land enough hits on an enemy, you are able to kick them down. Pedestrian characters will always attack you unarmed, as will certain gang members.
There is not much worth saying about this weapon slot, other than it is your very basic medium of combat in the game.
