Expel air (6)
I believe the answer is:
exhale
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">expel air</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for exhale that I've seen before include "send forth wind" , "Emit breath" , "Discharge" , "let breath out" , "Give out" .)