Tra từ betray - Từ điển Oxford Advanced Learner 8th

be·tray [betray betrays betrayed betraying] BrE [bɪˈtreɪ] NAmE [bɪˈtreɪ] verb
1. to give information about sb/sth to an enemy
•~ sb/sth He was offered money to betray his colleagues.
•~ sb/sth to sb For years they had been betraying state secrets to Russia.
2. ~ sb/sth to hurt sb who trusts you, especially by not being loyal or faithful to them
•She felt betrayed when she found out the truth about him.
•She betrayed his trust over and over again.
•I have never known her to betray a confidence (= tell other people sth that should be kept secret).
3. ~ sth to ignore your principles or beliefs in order to achieve sth or gain an advantage for yourself
•He has been accused of betraying his former socialist ideals.
4. to tell sb or make them aware of a piece of information, a feeling, etc, usually without meaning to
Syn: give away
•~ sth His voice betrayed the worry he was trying to hide.
•~ yourself She was terrified of saying something that would make her betray herself (= show her feelings or who she was).
Verb forms:

Word Origin:
Middle English: from ↑be- ‘thoroughly’ + obsolete tray ‘betray’, from Old French trair, based on Latin tradere ‘hand over’.

Thesaurus:
betray verb T (disapproving)
•She betrayed my trust.
•He betrayed his country.
disapproving deceive • • cheat • • let sb down • • stab sb in the back • |informal, disapproving tell • • blab • |formal, often disapproving inform on sb • |BrE turn King's/Queen's evidence • |AmE turn State's evidence • |AmE, informal finger • |BrE, slang, disapproving grass • |informal, approving, especially journalism blow the whistle on sb •
betray sb/blab/grass to sb
tell/inform/grass/blow the whistle on sb
feel betrayed/cheated/let down

Synonyms:
cheat
fool • deceive • betray • take in • trick • con
These words all mean to make sb believe sth that is not true, especially in order to get what you want.
cheat • to make sb believe sth that is not true, in order to get money or sth else from them: ▪ She is accused of attempting to cheat the taxman. ◇ ▪ He cheated his way into the job.
Cheat also means to act in a dishonest way in order to gain an advantage, especially in a game, competition or exam: ▪ You're not allowed to look at the answers— ▪ that's cheating ▪.
fool • to make sb believe sth that is not true, especially in order to laugh at them or to get what you want: ▪ Just don't be fooled into investing any money with them.
deceive • to make sb believe sth that is not true, especially sb who trusts you, in order to get what you want: ▪ She deceived him into handing over all his savings.
betray • to hurt sb who trusts you, especially by deceiving them or not being loyal to them: ▪ She felt betrayed when she found out the truth about him.
take sb in • [often passive] to deceive sb, usually in order to get what you want: ▪ I was taken in by her story.
trick • to deceive sb, especially in a clever way, in order to get what you want.
con • (informal) to deceive sb, especially in order to get money from them or get them to do sth for you: ▪ They had been conned out of £100 000.
which word?
Many of these words involve making sb believe sth that is not true, but some of them are more disapproving than others. Deceive is probably the worst because people typically deceive friends, relations and others who know and trust them. People may feel cheated/betrayed by sb in authority who they trusted to look after their interests. If sb takes you in, they may do it by acting a part and using words and charm effectively. If sb cheats/fools/tricks/cons you, they may get sth from you and make you feel stupid. However, sb might fool you just as a joke; and to trick sb is sometimes seen as a clever thing to do, if the person being tricked is seen as a bad person who deserves it.
to cheat/fool/trick/con sb out of sth
to cheat/fool/deceive/betray/trick/con sb into doing sth
to feel cheated/fooled/deceived/betrayed/tricked/conned
to fool/deceive yourself
to cheat/trick/con your way into sth

Example Bank:
•I have never known him to betray a confidence.
•She was terrified of saying something that would make her betray herself.