From Longman Dictionary of Contemporary Englishbetraybe‧tray /bɪˈtreɪ/ ●●○ verb [transitive] 1 friendsBETRAY to be disloyal to someone who trusts you, so that they are harmed or upset He felt that she had betrayed him.betray somebody to somebody What kind of man would betray his own sister to the police? She had betrayed her parents' trust. I would never betray a confidence (=tell a secret that someone has trusted me with).2 countryBETRAY to be disloyal to your country, company etc, for example by giving secret information to its enemies people who betray their country for money3 emotionsSHOW A FEELING OR ATTITUDE to show feelings that you are trying to hide SYN give away His voice betrayed his nervousness. His face betrayed nothing (=showed no emotion).4 truth to show that something is true or exists, especially when it is not easily noticed SYN give away The slightest sound might betray his presence. The crumpled sheets betrayed the fact that someone had been sleeping there.5 → betray your beliefs/principles/ideals etc —betrayer noun [countable]→ See Verb table
Examples from the Corpus
betray• When I heard what she had said about me I felt angry and betrayed.• The documents betray a deep anti-Semitism in the country.• Barker's comments on Germany betrayed a woeful ignorance of history and recent politics.• He is the golden youth whose promise is betrayed by his base appetites.• He had felt betrayed by the visit, after hoping to be lifted out of his crushing depression by it.• Olga's best friend betrayed her to the secret police.• They could see that her body was already betraying her.• Greene was denounced for betraying his Catholic beliefs and siding with the Communists.• The former federal agent betrayed his country and gave away vital military secrets.• He betrayed his friends in order to save his own life.• His words were calm, but his voice betrayed his very real concern and anxiety.• If he feels any bitterness, his voice doesn't betray it.• Women can not betray me, for I have never made the mistake of trusting them.• My husband lied to me and betrayed me.• I still have bitter feelings for Robert. What can I say? He completely betrayed my trust.• The new government has betrayed the ideals of the revolution.• There are people who are prepared to betray their country for money.• Not by the slightest word or look did she betray to Miss Miggs that she knew she couldn't read.• Conservatives felt betrayed when Bush raised taxes.betrayed ... trust• Adrian is shocked that Yasmin betrayed his trust.• He was absolved, neither waking nor sleeping had he betrayed his trust.• They needed a servant to replace that girl Jane who had betrayed her trust.• The National Trust has already betrayed its trust, albeit accidentally, by allowing the building to burn down.betray his presence• He held his breath, not wanting to make the slightest sound that might betray his presence.• He veered to his right, not wanting to betray his presence with dust from the dry mud of the lane.Origin betray (1200-1300) tray “to betray” ((13-16 centuries)), from Old French traïr, from Latin tradere; → TRAITOR 