A person who leads, especially someone who is in charge of a country, a company, or a military force, or anyone who has commanding authority or influence.

First and foremost, a leader leads people -- not company profits, not bullets or bombs, and not laws. A leader who forgets this -- who starts to think of the people under his or her command as numbers, poll results, monetary units, or acceptable casualties -- will no longer be an effective leader. His or her "subjects" (for lack of a better word) will know that the leader no longer gives a damn about them, and will begin to no longer give a damn about the company, squad, country, etc.

A good leader leads by example and inspiration.