Promoted by firm for masterful move (4)
I believe the answer is:
coup
'masterful move' is the definition.
(I've seen this in another clue)
'promoted by firm' is the wordplay.
'promoted' becomes 'up' (moving up).
'by' says to put letters next to each other.
'firm' becomes 'co' (abbreviation for company).
'up' after 'co' is 'COUP'.
'for' is the link.
(Other definitions for coup that I've seen before include "Successful exploit or action" , "Accomplishment, exploit" , "Sudden success" , "Stroke of genius" , "A successful action or revolt" .)