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