Bitterly pungent (5)
I believe the answer is:
acrid
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bitterly pungent</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 acrid that I've seen before include "Direly pungent" , "Astringent" , "Strong and sharp" , "irritating" , "Bitterly pungent" .)