Nanny : goat :: ___ : sheep (3)
I believe the answer is:
ewe
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">nanny goat</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >'<span class="explanation-format__original">sheep</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(a ewe is a female sheep)</span><br/ ><br/ ></span>
(Other definitions for ewe that I've seen before include "Lamb's dam" , "Directions" , "Palindrome for a female sheep" , "creature" , "She'll provide material to knit" .)