Fairy king (6)
I believe the answer is:
oberon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fairy king</span>' is the definition.<br/ ><span class="explanation-format__explanation">(Oberon is a mythical fairy king)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for oberon that I've seen before include "charming king" , "MND fairy king" , "...[IN DREAM] with king" , "Titania's husband" , "Fairy king (AMND)" .)