Ventilate (3)
I believe the answer is:
air
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ventilate</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for air that I've seen before include "show" , "Sky" , "Bearing; tune" , "A tune or attitude" , "Song - atmosphere" .)