End of an ultimatum (4)
I believe the answer is:
else
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">end of an ultimatum</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 else that I've seen before include "In addition, besides" , "Adverb meaning if not, otherwise" , "As an alternative" , "Besides; instead" , "Besides, otherwise" .)