Disagree with an attitude at work (6)
I believe the answer is:
oppose
'disagree with' is the definition.
(thesaurus)
'an attitude at work' is the wordplay.
'an attitude' becomes 'pose' (I've seen this before).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'work' becomes 'op' (abbreviation for opus).
'pose' after 'op' is 'OPPOSE'.
(Other definitions for oppose that I've seen before include "Counter" , "Bar" , "Obstruct, resist" , "match" , "Resist or fight against" .)