Moral obligation (4)
I believe the answer is:
duty
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">moral obligation</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for duty that I've seen before include "Obligation; levy" , "charge" , "Is one bound" , "Tax on goods" , "Financial or work obligation" .)