Tsarist edict (5)
I believe the answer is:
ukase
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tsarist edict</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ukase that I've seen before include "Old Russian edict" , "Official or arbitrary decree" , "Decree (originally from the Tsar)" , "Legal order" , "Tsarist decree; sea UK (anag.)" .)