Simpson imp (4)
I believe the answer is:
bart
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">simpson imp</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 bart that I've seen before include "Son in The Simpsons" , "Branch of Islam" , "Small title-holder being a brat" , "Homer's son" .)