Seat in Devonshire Arms (4)
I believe the answer is:
rear
'seat' is the definition.
(synonyms)
'in devonshire arms' is the wordplay.
'in' says the answer is hidden in the clue.
'REAR' is hidden in the letters of 'devonshire arms'.
(Other definitions for rear that I've seen before include "Breed or bring up" , "early, long before now" , "Bring up or stand up on hind legs" , "Rare at the back" , "Rise up at the back" .)