Green’s Dictionary of Slang

(orig. US) to rescue someone.

1974		V.E. Smith Jones Men 150: I’m just laying back hoping the snitch will get his ass over there and bail me out.
1981		S. Berkoff Decadence in Decadence and Other Plays (1985) 14: Don’t drag your ma and pa from out their graves to bail you out for all the shit.
1994		N. McCall Makes Me Wanna Holler (1995) 377: As long as he knows you’re going to bail him out, he’ll continue getting into jams.
2000		Guardian Guide 22–28 Jan. 28: I bail his sorry arse out and how does he repay me?