Threat finale (2,4)
I believe the answer is:
or else
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">threat finale</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 or else that I've seen before include "Statement that threatens" , "Do it . . . . . . - an informal warning" , "Threatening phrase" , "If not, then - vaguely threatening" , "Alternatively" .)