Trip, falter (7)
I believe the answer is:
stumble
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">trip</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that trip can be written as stumble)</span><br/ ><br/ >'<span class="explanation-format__original">falter</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for stumble that I've seen before include "Fall while walking or running" , "Falter" , "Momentarily trip" , "Trip and almost fall" , "Come near to falling while walking" .)