officer

An officer is a person in an army who has much authority. A general and a captain are two types of officers.

Example: A soldier must obey his commanding officer.

An officer is a policeman, often called a "police officer." (Note, "officer" is often better than "policeman" because the officer could be a woman or a man.)

Example: Officer, can you help me, I've been robbed.

An officer is someone who holds office (meaning, has authority).

Example: The judge is an important officer of the court.