‘效忠’ is a formal, literary verb meaning ‘to pledge allegiance’ or ‘to swear loyalty’ to a person, cause, organization, or principle. It combines two characters: 效 (xiào), meaning ‘to serve’ or ‘to devote oneself to’, and 忠 (zhōng), meaning ‘loyalty’ or ‘fidelity’. Together, they convey the idea of wholehearted, active devotion—not just passive belief, but committed service grounded in faithfulness.

This term is commonly used in political, historical, military, or organizational contexts—such as pledging loyalty to a nation, monarch, party, or leader. It carries strong moral weight and solemnity; it’s rarely used in casual speech or personal relationships (e.g., you wouldn’t say ‘效忠朋友’). In modern usage, it often appears in official documents, oaths, historical narratives, or media commentary on leadership and ideology.