Get-out-of-jail money (4)
I believe the answer is:
bail
'get-out-of-jail money' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bail that I've seen before include "small bar on field" , "Temporary release of an accused person on conditions" , "Topper for stumps" , "Surety - part of wicket - scoop" , "Sum of money guaranteeing the accused's return to court" .)