In case, for fear that (4)
I believe the answer is:
lest
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">in case</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(eg 'lest we forget')</span><br/ ><br/ >'<span class="explanation-format__original">for fear that</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for lest that I've seen before include "In case" , "For fear that (something should happen)" , "In order not to, to avoid the risk that" , "To avoid the risk that - let's do it" , "For fear that; in order to prevent" .)