Pixie, sprite (3)
I believe the answer is:
elf
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">pixie</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">sprite</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(an elf is a sprite)</span><br/ ><br/ ></span>
(Other definitions for elf that I've seen before include "He causes mischief" , "Mischievous fairy No.2" , "Woodland sprite" , "Hobgoblin" , "Mischievous fairies" .)