Sickly look
I believe the answer is:
pallor
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sickly look</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pallor that I've seen before include "Ashen complexion due to illness" , "showing whiteness" , "Paleness of complexion" , "Whiteness of face as from illness" , "Unnatural lack of colour in the skin" .)