Unlikely to change (3)
I believe the answer is:
set
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unlikely to change</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 set that I've seen before include "box?" , "Ready" , "Firm, like jelly" , "Harden; fixed; group" , "Major unit of tennis match" .)