Character Look is an item type that allows you to change your main character's appearance (e.g. playing as a man or woman). Check the relevant Shop section for details.
All Character Looks share the same items, skills, trophies, etc. except clothes. Character Looks that differ from Jason (default) can also provide a number of passive bonuses that affect different aspects of the game.
Note that when you start a Story mission as anyone but Jason, the Character Look automatically swaps to Jason for the duration of the mission.