Piercing scream (6)
I believe the answer is:
shriek
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">piercing scream</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for shriek that I've seen before include "Scream of pain or delight" , "Sharp piercing cry" , "Short piercing scream" , "Hikers (anag.)" , "Shrill cry or scream" .)