Young feline (6)
I believe the answer is:
kitten
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">young feline</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 kitten that I've seen before include "Little feline" , "Young of a beaver" , "Baby rabbit" , "Fluffy little animal" , "youngster" .)