Not showy (6)
I believe the answer is:
modest
'not showy' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for modest that I've seen before include "Reserved" , "'Unassuming, diffident (6)'" , "Mussorgsky, nominally?" , "Humble, not pretentious or showy" , "Humble, unpretentious" .)