Definition

1. Verb:

   • To betray: To be disloyal or unfaithful to someone who trusts you, such as a friend, partner, or ally, by acting against their interests or revealing their secrets.
   • To commit treason: To betray one's country, nation, or a sacred cause, often by aiding an enemy.

2. Noun:

   • Betrayal / Treason: The act or instance of being traitorous or disloyal.

Usage Examples

• Verb:
  • Anh ta đã phản bội bạn bè. (He betrayed his friends.)
  • Phản bội tổ quốc là tội nặng nhất. (To betray one's homeland is the gravest crime.)
• Noun:
  • Sự phản bội của hắn không thể tha thứ. (His betrayal is unforgivable.)

Advanced Usage

• The word carries a strong moral condemnation and implies a profound breach of trust, duty, or oath.
• It is often used in contexts of politics, war, and deep personal relationships (e.g., romance, friendship).

Variants and Related Words

• Kẻ phản bội (n): traitor, betrayer.
  • Hắn bị coi là kẻ phản bội. (He is considered a traitor.)
• Sự phản bội (n): the act of betrayal.

Synonyms

• Betray: to be disloyal.
• Be unfaithful: to break faith, especially in a relationship.
• Commit treason: to betray one's country.

Antonyms

• Trung thành (adj): loyal, faithful.
• Bảo vệ (v): to protect, to defend.

Related Idioms and Phrases

• Phản bội lời thề: to break/violate an oath; to betray a vow.
  • Phản bội lời thề là hành động đáng khinh. (Betraying an oath is a despicable act.)
• Phản bội lý tưởng: to betray an ideal or a cause.
  • Hành động đó đồng nghĩa với phản bội lý tưởng. (That action is synonymous with betraying the cause.)