Careful and persistent effort (9)
I believe the answer is:
diligence
'careful and persistent effort' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for diligence that I've seen before include "Old stagecoach" , "Thoroughgoing application" , "that could be due?" , "Industriousness" , "Careful and persistent work or effort" .)