Levy of one tenth (5)
I believe the answer is:
tithe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">levy of one tenth</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tithe that I've seen before include "Tax once levied" , "It used to decimate income" , "Tax paid to church" , "Tenth part - old tax" , "Ancient tax" .)