Creative skill in work, to some extent (6)
I believe the answer is:
partly
'to some extent' is the definition.
(I've seen this before)
'creative skill in work' is the wordplay.
'creative skill' becomes 'art' (I've seen this before).
'in' indicates putting letters inside.
'work' becomes 'ply' (I've seen this before).
'art' placed within 'ply' is 'PARTLY'.
(Other definitions for partly that I've seen before include "'In some degree, not wholly (6)'" , "Not quite" , "to a certain degree" , "Somewhat" , "To some extent, not wholly" .)