Perspiration (5)
I believe the answer is:
sweat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">perspiration</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sweat that I've seen before include "Salty fluid secreted by glands" , "It's hard work" , "(Of argument) intense" , "Trouble in Australia" , "Soldier" .)