Soundly ridicules appearance (5)
I believe the answer is:
guise
'appearance' is the definition.
(I know that guise is a type of color)
'soundly ridicules' is the wordplay.
'soundly' indicates a 'sounds like' (homophone) clue.
'ridicules' becomes 'guys' (I've seen this before).
'guys' sounds like 'GUISE'.
(Other definitions for guise that I've seen before include "General appearance" , "Shape; pretence" , "Show" , "Semblance; likeness" , "Mask" .)