One taking satisfaction in making an avenue green, perhaps (7)
I believe the answer is:
avenger
'one taking satisfaction in' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'an avenue green perhaps' is the wordplay.
'an avenue' becomes 'av'.
'perhaps' is an anagram indicator.
'green' anagrammed gives 'enger'.
'av'+'enger'='AVENGER'
'making' is the link.
Can you help me to learn more?
(Other definitions for avenger that I've seen before include "One inflicting retribution" , "Someone seeking to settle a score" , "One who retaliates -- engrave (anag)" , "one seeking to get even" , "One who exacts reparation for a wrong" .)