Strict, severe (5)
I believe the answer is:
stern
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">strict</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">severe</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for stern that I've seen before include "enforcing submission" , "Grimly serious; back" , "Where sailors may be" , "Back end of a ship" , "Strict, grimly serious" .)