Refusal to lift tax for working (2,4)
I believe the answer is:
on duty
'working' is the definition.
(thesaurus)
'refusal to lift tax' is the wordplay.
'refusal' becomes 'no'.
'to lift' is a reversal indicator (in a down clue, letters lift up).
'tax' becomes 'duty' (duty is a kind of tax).
'no' reversed gives 'on'.
'on'+'duty'='ON-DUTY'
'for' is the link.
(Other definitions for on duty that I've seen before include "As working policemen are" , "(Of soldier) working" , "Working at a particular time" , "What working nurses are" , "Engaged in one's regular work" .)