Stuffy (7)
I believe the answer is:
airless
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stuffy</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for airless that I've seen before include "Lacking ventilation" , "Close" , "not a breath of wind" , "Very stuffy" , "Stifling" .)