Nobody disputes it's the equivalent of a deadly sin (6)
I believe the answer is:
agreed
'nobody disputes it's the equivalent' is the definition.
I can't tell whether this defines the answer.
'a deadly sin' is the wordplay.
'deadly sin' becomes 'greed' (greed is a kind of deadly sin).
'a'+'greed'='AGREED'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for agreed that I've seen before include "Consented, settled" , "Was fitting" , "Consented and concurred" , "Expressed willingness" , "Tallied - reconciled" .)