Supplying online banter? (9)
I believe the answer is:
equipping
'supplying' is the definition.
(equipping is a kind of supplying)
'online banter?' is the wordplay.
'online' becomes 'e' (abbreviation for electronic, e.g. in ecommerce).
'banter?' becomes 'quipping' (making funny quips).
'e'+'quipping'='EQUIPPING'
(Other definitions for equipping that I've seen before include "Providing essential tools" , "supplying what is needed" .)