‘背叛’ is a compound verb meaning 'to betray' — to break trust, loyalty, or duty toward someone or something. The first character 背 (bèi) literally means 'back' but here carries the sense of 'turning one's back on', implying rejection or abandonment. The second character 叛 (pàn) means 'to rebel' or 'to revolt', emphasizing defiance against authority, allegiance, or agreement. Together, they convey a strong moral violation — not just a simple mistake, but a deliberate, often hurtful act of disloyalty.

This word is commonly used in serious contexts: romantic relationships (e.g., cheating), politics (e.g., treason), friendship (e.g., revealing secrets), or ideological commitments (e.g., abandoning one’s principles). It carries strong negative emotional weight and implies deep disappointment or moral judgment. While it can function as a noun ('betrayal'), it most frequently appears as a verb, often with subjects like people, groups, or abstract ideals (e.g., 'country', 'promise', 'friendship').