Merciful, having left me spinning coin outside (7)
I believe the answer is:
clement
'merciful' is the definition.
(associated in meaning)
'left me spinning coin outside' is the wordplay.
'left me spinning' becomes 'lem' (I can't explain this - if you can you should believe this answer much more).
'coin' becomes 'cent' (cent is a kind of coin).
'outside' indicates putting letters inside.
'lem' put into 'cent' is 'CLEMENT'.
'having' is the link.
Can you help me to learn more?
(Other definitions for clement that I've seen before include "Temperate" , "Mild or balmy" , "Fine" , "Fair" , "Patron saint of tanners" .)