To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly; as, an officer betrayed the city.

To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive; as, to betray a person or a cause.

deliver to an enemy by treachery; "Judas sold Jesus"; "The spy betrayed his country"

be sexually unfaithful to one's partner in marriage; "She cheats on her husband"; "Might her husband be wandering?"

give away information about somebody; "He told on his classmate who had cheated on the exam"

cause someone to believe an untruth; "The insurance company deceived me when they told me they were covering my house"