Leave pocketing old ring (5)
I believe the answer is:
quoit
'leave pocketing old ring' is the definition.
I can't judge whether this definition defines the answer.
'leave pocketing old ring' is the wordplay.
'leave' becomes 'quit' (synonyms).
'pocketing' is an insertion indicator (pocket can mean to steal or take possession of).
'old ring' becomes 'o' (letter resembling a ring. I am not sure about the 'old' bit.).
'quit' going around 'o' is 'QUOIT'.
Can you help me to learn more?
(Other definitions for quoit that I've seen before include "Ring used in shipboard game" , "Flat ring" , "Ring for throwing in game" , "Cast rings" , "Rubber ring thrown to encircle peg in game" .)