Shrill insect (6)
I believe the answer is:
cicada
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">shrill insect</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 cicada that I've seen before include "Chirpy type" , "Large bug" , "Insect, produces high-pitched drone" , "Noisy tropical insect" , "Shrill insect" .)