Discourage an insincere attitude to work (6)
I believe the answer is:
oppose
'discourage' is the definition.
(thesaurus)
'an insincere attitude to work' is the wordplay.
'an insincere attitude' becomes 'pose' (attitude can mean a pose or stance. I am not sure about the 'insincere' bit.).
'to' says to put letters next to each other (I've seen this in other clues).
'work' becomes 'op' (abbreviation for opus).
'pose' put after 'op' is 'OPPOSE'.
Can you help me to learn more?
(Other definitions for oppose that I've seen before include "Counter" , "Refute - confront" , "Compete with" , "Take stand against, resist" , "match" .)