Female swan (3)
I believe the answer is:
pen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">female swan</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 pen that I've seen before include "record" , "Animal enclosure" , "dash off" , "'The ... is mightier than the sword'" , "Writing tool" .)