Divisible by two (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">divisible by two</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 even that I've seen before include "Peaceful" , "(Of a number) divisible by 2" , "Flattened" , "When darkness starts to fall" , "Tied" .)