Ridicule about six as extravagant (6)
I believe the answer is:
lavish
'extravagant' is the definition.
('lavish' can be a synonym of 'extravagant')
'ridicule about six' is the wordplay.
'ridicule' becomes 'lash'.
'about' is an insertion indicator.
'six' becomes 'vi' ('vi' can be a synonym of 'six').
'lash' enclosing 'vi' is 'LAVISH'.
'as' is the link.
(Other definitions for lavish that I've seen before include "Extremely generous" , "Plentiful or extravagent" , "Lash around Vi is extravagant (6)" , "Generous - liberal" , "Heap (money)" .)