Gaudy or loud (6)
I believe the answer is:
garish
I believe this clue is a double definition.
'gaudy' is the first definition.
(I know that gaudy can be written as garish)
'loud' is the second definition.
(I know that loud can be written as garish)
(Other definitions for garish that I've seen before include "Bright and showy" , "Excessively bright, over-colourful (6)" , "Tastelessly showy" , "Gaudy, lurid" , "Cheap, flash" .)