Frighten, alarm (5)
I believe the answer is:
scare
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">frighten</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that frighten can be written as scare)</span><br/ ><br/ >'<span class="explanation-format__original">alarm</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for scare that I've seen before include "Health worry" , "Cause fright, alarm" , "Frighten, alarm" , "Panic" , "Greatly frighten" .)