Hot day (8)
I believe the answer is:
scorcher
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hot day</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for scorcher that I've seen before include "sweltering day" , "for example, really fine" , "heat wave" , "Day of very hot and sunny weather" , "Very hot day; remarkable thing" .)