Eater (5)
I believe the answer is:
diner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">eater</span>' is the definition.<br/ ><span class="explanation-format__explanation">(diner is a kind of eater)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for diner that I've seen before include "Buffet car" , "American cafe" , "(Person eating in) restaurant" , "US eatery" , "one taking several courses" .)