Arguably, only half are used skilfully (4)

I believe the answer is:

ably

I'm a little stuck... Click here to teach me more about this clue!

'skilfully' is the definition.

'arguably only half are' is the wordplay.
'ABLY' is hidden within the letters.
But, I am not sure how the hidden word is indicated.

'used' is the link.

Can you help me to learn more?

(Other definitions for ably that I've seen before include "In proficient manner" , "With competence" , "Competently" , "Masterfully" , "With great skill" .)

I've seen this clue in The Irish Times.

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.