
1. The literal use of bail/bale is to abandon abruptly as in making an emergency exit from an aeroplane in a parachute.
2. The literal meaning of to bail out is to remove water from a leaky boat.
3. It is now more common to use bail in a figurative/metaphorical sense:
The minister has bailed on the government's housing policy (announced his opposition).

4. 'Bail out' is also used metaphorically but usually with a closer connection to the literal meaning: The pilot bailed out of his plane but not Bob has bailed out on us and gone home.
5. The noun is sometimes spelled as one word: bailout.
6. There is a dispute over the spelling of bail and bale - bail is probably used more frequently but both are allowed by most dictionaries.