Plunder part of subsidiary in recession (4)
I believe the answer is:
raid
'plunder' is the definition.
(thesaurus)
'part of subsidiary in recession' is the wordplay.
'part of' says the answer is hidden in the clue.
'in recession' shows that the letters should be reversed in order.
'diar' is hidden in the letters of 'subsidiary'.
'diar' reversed gives 'RAID'.
(Other definitions for raid that I've seen before include "Maraud" , "Surprise police visit" , "Stock Exchange activity" , "Finch and Bronson starred in . . . . On Entebbe" , "Enter a territory and take spoils" .)