Mortal sin (7)
I believe the answer is:
avarice
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mortal sin</span>' is the definition.<br/ ><span class="explanation-format__explanation">(avarice is a kind of mortal sin)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for avarice that I've seen before include "Insatiable desire for wealth" , "A deadly sin" , "Cupidity" , "Greed, covetousness" , "Insatiable lust" .)