Might criminal jump this wooden bar? (4)
I believe the answer is:
bail
'wooden bar?' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for bail that I've seen before include "Temporary release of an accused person on conditions" , "Temporary release of the accused - wicket crosspiece" , "Topper for stumps" , "one puts up then another jumps?" , "Crosspiece on a 14 across" .)