Pronunciation: (loi'ul),[key] —adj. 1. faithful to one's sovereign, government, or state: a loyal subject. 2. faithful to one's oath, commitments, or obligations: to be loyal to a vow. 3. faithful to any leader, party, or cause, or to any person or thing conceived as deserving fidelity: a loyal friend. 4. characterized by or showing faithfulness to commitments, vows, allegiance, obligations, etc.: loyal conduct.