Bygone days (4)
I believe the answer is:
past
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bygone days</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for past that I've seen before include "Second visitor in 5 [A CHRISTMAS CAROL]" , "Gone by in time" , "tense" , "The time that has elapsed" , "Bygone" .)