Word in an ultimatum (6)
(Other definitions for unless that I've seen before include "Except, save" , "Conjunction meaning except when" , "Otherwise than if" , "bar" , "Though" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">word in 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 "Alternatively" , "Eels (anag)" , "Besides; instead" , "Besides; different" , "In addition; different" .)