Cry of rook perhaps, possessing large talon (4)
I believe the answer is:
claw
'talon' is the definition.
(claw belonging to a bird)
'cry of rook perhaps possessing large' is the wordplay.
I cannot really see how this works, but
'large' could be 'l' (eg in clothes sizes) and 'l' is present in the answer.
'cry' could be 'caw' (caw is a kind of cry) and 'caw' is present in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for claw that I've seen before include "Talon" , "Rake" , "Bird's foot" , "Crab's pincer" , "Lobster's pincer" .)