Caterpillar? (5)
I believe the answer is:
larva
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">caterpillar?</span>' is the definition.<br/ ><span class="explanation-format__explanation">(caterpillar is a kind of larva)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for larva that I've seen before include "early form" , "Immature life form" , "Immature form of caterpillar" , "Maggot" , "Animal in immature state" .)