Egg of a louse (3)
I believe the answer is:
nit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">egg of a louse</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 nit that I've seen before include "Egg of a head louse" , "Parasite's egg made of tin" , "Louse's egg; idiot" , "Louse; fool" , "Louse-egg" .)