What is a synonym for betray?

Here are some synonyms for betray, depending on the context:

General betrayal:

* Deceive

* Double-cross

* Betray

* Violate

* Break faith

* Go back on

* Stab in the back

* Sell out

* Turn against

* Forsake

Betrayal of trust:

* Abandon

* Disappoint

* Fail

* Let down

* Break a promise

* Be untrue to

Betrayal of a secret:

* Disclose

* Reveal

* Expose

* Spill the beans

* Give away

Betrayal of a country or cause:

* Subvert

* Sabotage

* Traitor

* Turncoat

* Renege

The best synonym for "betray" will depend on the specific situation and the nuance you want to convey.