Lurid (6)
I believe the answer is:
garish
'lurid' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for garish that I've seen before include "Brashly bright" , "Excessively bright, over-colourful (6)" , "Gaudy, over-decorated" , "Colourful in a vulgar manner" , "Gaudy, showy" .)