Thin, emaciated (4)
I believe the answer is:
bony
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">thin</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">emaciated</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for bony that I've seen before include "Osseous" , "With skeleton showing through" , "[GAUNT] ?" , "Skeletal" , "Angular" .)