A department's accepting money returned with skill (9)
I believe the answer is:
adeptness
'skill' is the definition.
(I've seen this before)
'a department's accepting money returned' is the wordplay.
'department's' becomes 'dept's'.
'accepting' means one lot of letters goes inside another.
'money' becomes 'sen' (I've seen this before).
'returned' says the letters should be written in reverse.
'sen' in reverse letter order is 'nes'.
'depts' placed around 'nes' is 'deptness'.
'a'+'deptness'='ADEPTNESS'
'with' acts as a link.
(Other definitions for adeptness that I've seen before include "Deftness, adroitness" , "complete skill" .)