British imperialism absorbs the fellow (3)
I believe the answer is:
him
'the fellow' is the definition.
'british imperialism absorbs' is the wordplay.
'absorbs' says the answer is hidden in the clue.
'HIM' is hidden within 'british imperialism'.
(Other definitions for him that I've seen before include "Proper character" , "That man" , "Objective male pronoun" .)