Louse egg (3)

I believe the answer is:
nit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">louse egg</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 nit that I've seen before include "Louse-egg" , "Young louse" , "Egg of a head louse" , "small egg" , "Stupid person; egg" .)