Gets colder (5)
I believe the answer is:
cools
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gets colder</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 cools that I've seen before include "Loses heat" , "Becomes less ardent" , "Chills" , "Gets colder" .)