Move jug (4)
I believe the answer is:
stir
This clue is a double definition.
'move' is the first definition.
(stir can mean to make a movement)
'jug' is the second definition.
(both are slang for prison)
(Other definitions for stir that I've seen before include "jail" , "move very slightly, or agitate" , "Start to move" , "Whisk, agitate" , "in which you'll find people with convictions" .)