Australian against Erica, affected by greed (7)
I believe the answer is:
avarice
'greed' is the definition.
(avarice is a kind of greed)
'australian against erica affected' is the wordplay.
'australian' becomes 'A'.
'against' becomes 'v' (abbreviation for 'versus').
'affected' is an anagram indicator.
'erica' anagrammed gives 'arice'.
'a'+'v'+'arice'='AVARICE'
'by' is the link.
(Other definitions for avarice that I've seen before include "Stinginess" , "Greed - caviare (anag)" , "One of seven deadly sins" , "Greed, covetousness" , "Insatiable desire for wealth" .)