Least fresh (7)
I believe the answer is:
stalest
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">least fresh</span>' is the definition.<br/ ><span class="explanation-format__explanation">('stale' is the opposite of 'fresh' so 'stalest' should be a synonym for 'least fresh')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stalest that I've seen before include "Least original" , "Most unoriginal" .)