In a legal context, referring to the release of a prisoner:
* Bond
* Release
* Surety
* Security
In a nautical context, referring to removing water from a boat:
* Bale (archaic)
* Pump (more general)
* Scooping
* Drain
In a more general context, referring to abandoning something:
* Abandon
* Desert
* Escape
* Quit
In a casual context, referring to helping someone out of a difficult situation:
* Help
* Rescue
* Assist
* Support
It's important to consider the specific context and the intended meaning when choosing a synonym for "bail."