Quiet existence of artwork (5,4)
I believe the answer is:
still life
'artwork' is the definition.
(I've seen this before)
'quiet existence' is the wordplay.
'quiet' becomes 'still' (still is a kind of quiet).
'existence' becomes 'life' (life is a kind of existence).
'still'+'life'='STILL-LIFE'
'of' is the link.
(Other definitions for still life that I've seen before include "work of art" , "rt-form" , "artwork" , "Painting genre" , "Painting of inanimate things like fruit or flowers" .)