Breakaway (12)
I believe the answer is:
secessionist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">breakaway</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for secessionist that I've seen before include "One breaking away from a federation" , "SNP type?" .)