military officer, officer -- (any person in the armed services who holds a position of authority or command; "an officer is responsible for the lives of his men")
officeholder, officer -- (someone who is appointed or elected to an office and who holds a position of trust; "he is an officer of the court"; "the club elected its officers for the coming year")
policeman, police officer, officer -- (a member of a police force; "it was an accident, officer")
officer, ship's officer -- (a person authorized to serve in a position of authority on a vessel; "he is the officer in charge of the ship's engines")