Deny rejecting official employment (3)
I believe the answer is:
use
'employment' is the definition.
(how something is used)
'deny rejecting official' is the wordplay.
'deny' becomes 'refuse' (deny can mean to refuse or reject).
'rejecting' indicates named letters should be taken away.
'official' becomes 'ref' (match official in football, say).
'refuse' with 'ref' taken out is 'USE'.
(Other definitions for use that I've seen before include "Milk" , "Application" , "Employment; utilise" , "Exploit; custom" , "exercise" .)