Trouble in prison (4)
I believe the answer is:
stir
I believe this is a double definition.
'trouble' is the first definition.
(thesaurus)
'prison' is the second definition.
(informal term for prison)
'in' acts as a link.
(Other definitions for stir that I've seen before include "Arouse (a memory)" , "Wake; disturbance" , "prompt" , "Uproar" , "Whisk, blend" .)