Definition

1. Verb phrase:
   • To change one's feelings or loyalty: To alter one's affection, commitment, or allegiance towards a person, cause, or idea, often implying betrayal or fickleness.
   • To become unfaithful: Specifically used to describe breaking fidelity in a romantic relationship by shifting one's love or devotion to someone else.

Usage Examples

• Verb phrase:
  • Anh ấy đã thay lòng và yêu người khác. (He changed his heart and fell in love with someone else.)
  • Đừng bao giờ thay lòng với bạn bè. (Never change your loyalty towards friends.)
  • Cô ấy hứa sẽ không thay lòng đổi dạ. (She promised she would not be unfaithful or change her mind.)

Advanced Usage

• The phrase is often used in a moral or emotional context to criticize inconstancy. It carries a strong negative connotation of betrayal, especially in personal relationships.
• It is frequently paired with "đổi dạ" (to change one's inner self) in the fixed idiom "thay lòng đổi dạ" to emphasize a complete and profound change in one's heart and mind, underscoring deep unfaithfulness.

Variants and Related Words

• Thay lòng đổi dạ (idiomatic verb phrase): To be utterly unfaithful; to completely change one's heart and mind.
  • Kẻ phản bội đó đã thay lòng đổi dạ. (That traitor completely changed allegiance.)

Synonyms

• To be unfaithful: To break trust, especially in a relationship.
• To betray: To be disloyal to someone who trusts you.
• To change allegiance: To switch loyalty from one side to another.

Related Idioms

• Thay lòng đổi dạ: As above, this is the most common and reinforced form of the phrase.
• Thay lòng thay dạ: A less common variant with the same meaning as "thay lòng đổi dạ."