Tense, ill at ease (2,4)
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">tense</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(on edge can mean tense or stressed)</span><br/ ><br/ >'<span class="explanation-format__original">ill at ease</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(both can mean nervous)</span><br/ ><br/ ></span>
(Other definitions for on edge that I've seen before include "Apprehensive" , "Nervously excited" , "Cliff-top walker may be" , "Anxious, nervy" , "Highly strung" .)