Mild expletive — vermin (4)
I believe the answer is:
rats
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">mild expletive</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">vermin</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for rats that I've seen before include "Annoyed expression" , "Damn" , "deserters" , "Snoopy's imprecation - vermin" , "Curse" .)