Prison disturbance (4)
I believe the answer is:
stir
I believe this is a double definition.
'prison' is the first definition.
(informal term for prison)
'disturbance' is the second definition.
(stir can mean a commotion or disturbance)
(Other definitions for stir that I've seen before include "Disturb" , "bird" , "College" , "Commotion - prison" , "Big house" .)