Prison in order it seems, after reflection (4)
I believe the answer is:
stir
'prison' is the definition.
(informal term for prison)
'in order it seems after reflection' is the wordplay.
'in' indicates a hidden word.
'after reflection' says the letters should be written in reverse.
'rits' is hidden in the letters of 'order it seems'.
'rits' in reverse letter order is 'STIR'.
(Other definitions for stir that I've seen before include "move very slightly, or agitate" , "unrest" , "where porridge is served" , "Arouse; commotion" , "Rouse; prison (colloq.)" .)