Vivid — acute (7)
I believe the answer is:
intense
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">vivid</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that vivid can be written as intense)</span><br/ ><br/ >'<span class="explanation-format__original">acute</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that acute can be written as intense)</span><br/ ><br/ ></span>
(Other definitions for intense that I've seen before include "Extremely emotional" , "Fierce - deep" , "Acute difficulty" , "Forceful, concentrated" , "Extremely earnest or serious" .)