Piggery (3)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">piggery</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 sty that I've seen before include "Eye ailment or pig's home" , "Sore on eyelid" , "Enclosure for swine" , "Pig pen" , "Swinish place" .)