Airless (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">airless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that airless can be written as stuffy)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stuffy that I've seen before include "needing to be aired" , "Staid - airless" , "Airless - humourless" , "Airless; unadventurous" , "Old-fashioned" .)
(Other definitions for frowsty that I've seen before include "stuffy" , "Foul-smelling" .)