Gather enthusiast confronting family is an impertinent riddler (8,6)
I believe the answer is:
squirrel nutkin
'an impertinent riddler' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'gather enthusiast confronting family' is the wordplay.
'gather' becomes 'squirrel' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'enthusiast' becomes 'nut' (nut can mean an enthusiast or fan).
'confronting' is a charade indicator (letters next to each other).
'family' becomes 'kin' (synonyms).
'squirrel'+'nut'+'kin'='SQUIRREL NUTKIN'
'is' is the link.
Can you help me to learn more?
(Other definitions for squirrel nutkin that I've seen before include "Potter's creation" , "Beatrix Potter character" .)