Cave-dweller (5)
I believe the answer is:
troll
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cave-dweller</span>' is the definition.<br/ ><span class="explanation-format__explanation">(a troll might live in a cave)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for troll that I've seen before include "Ugly creature of folklore" , "Mythological being" , "Ugly character from Norse legend" , "Try to catch fish" , "Creature from Norse mythology" .)