Abnormally thin (9)
I believe the answer is:
emaciated
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">abnormally thin</span>' is the definition.<br/ ><span class="explanation-format__explanation">(emaciated means very thin)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for emaciated that I've seen before include "skinny" , "Very thin from starvation or illness" , "Gaunt from disease or hunger" , "wasted" , "of very little substance" .)