An operative who'll pass? (4)
I believe the answer is:
hand
This clue might be a double definition.
'an operative' is the first definition.
(I've seen this in other clues)
'who'll pass?' is the second definition.
'hand' can be an answer for 'pass?' (I've seen this before). I am not certain of the 'who'll' bit.
Can you help me to learn more?
(Other definitions for hand that I've seen before include "Limb extremity" , "Help < and applause" , "Index" , "Cards dealt to player" , "Manual worker" .)