Eg, nematode (4)
I believe the answer is:
worm
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">eg nematode</span>' is the definition.<br/ ><span class="explanation-format__explanation">(nematode is a kind of worm)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for worm that I've seen before include "Screw thread; maggot" , "Creeping invertebrate" , "Long slender invertebrate" , "Despicable fellow" , "Wriggly creature" .)