Respiration (6)
I believe the answer is:
breath
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">respiration</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for breath that I've seen before include "Air drawn in and expelled out" , "Bertha (anag.)" , "Air that's inhaled and exhaled" , "Bather (anag.)" , "Inhale and exhale air" .)