betray

verb

1. (transitive)To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly.

   “An officer betrayed the city.”

   “He betrayed his own sister to the secret police.”

2. (transitive)To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive.

   “to betray a person or a cause”

   “Quresh betrayed Sunil to marry Nuzhat.”

   “My eyes have been betraying me since I turned sixty.”

   “I maruell I heare no nevves of Dromio, either hee ſlackes the matter, or betrayes his maiſter, I dare not motion anie thing to Stellio, till I knovve vvhat my boy hath don; Ile hunt him out, if the loiterſacke be gone ſpringing into a tauerne, Ile fetch him reeling out.”

3. (transitive)To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.
4. (transitive)To disclose (a secret, etc.) in deliberate violation of someone’s confidence.

   “The dead leap at the throat, destroy The meaning of the day; dark forms Have scaled your walls, and spies betray Old secrets to amorphous swarms.”

5. (transitive)To disclose or indicate, for example something which prudence would conceal; to reveal unintentionally.

   “Though he had lived in England for many years, a faint accent betrayed his Swedish origin.”

   “Jones’ sad eyes betray a pervasive pain his purposefully spare dialogue only hints at, while the perfectly cast [Josh] Brolin conveys hints of playfulness and warmth while staying true to the craggy stoicism at the character’s core.”

   “Again, to take a less extreme example, there is no denying that although the dialects of northern France retained their fundamentally Romance character, they betray many Germanic influences in phonetics and vocabulary, […]”

6. (transitive)To mislead; to expose to inconvenience not foreseen; to lead into error or sin.
7. (transitive)To lead astray; to seduce (as under promise of marriage) and then abandon.