Sibling's daughter (5)
I believe the answer is:
niece
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sibling's daughter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for niece that I've seen before include "member of different generation" , "girl further down the line" , "Criminal" , "[PRIEST'S] daughter?" , "Female family member" .)