Rodent-catching cat (6)
I believe the answer is:
mouser
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rodent-catching cat</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 mouser that I've seen before include "Cat proficient at catching small rodents" , "Predatory cat" , "Cat as hunter of small rodents" , "Rodent catcher" , "Cat with certain skills" .)