Earnest application (9)

I believe the answer is:

diligence

(Other definitions for diligence that I've seen before include "hard effort" , "Thoroughgoing application" , "Careful and persistent work or effort" , "Industriousness" , "It takes steady application" .)

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.