React (7)
I believe the answer is:
respond
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">react</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that react can be written as respond)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for respond that I've seen before include "Write back" , "Answer back" , "Reply - react" , "Come back" , "React (positively) to a stimulus or treatment" .)