Caviare possibly causes greed (7)
I believe the answer is:
avarice
'greed' is the definition.
(avarice is a kind of greed)
'caviare possibly' is the wordplay.
'possibly' is an anagram indicator.
'caviare' with letters rearranged gives 'AVARICE'.
'causes' is the link.
(Other definitions for avarice that I've seen before include "Excessive greed for wealth" , "One of seven deadly sins" , "Stinginess" , "Eager desire" , "A deadly sin" .)