Stone thrown from relatively dignified artist's workshop (7)
I believe the answer is:
atelier
'artist's workshop' is the definition.
(I've seen this before)
'stone thrown from relatively dignified' is the wordplay.
'stone' becomes 'st'.
'thrown from' is a deletion indicator.
'relatively dignified' becomes 'statelier'.
'statelier' with 'st' removed is 'ATELIER'.
(Other definitions for atelier that I've seen before include "Artist's studio (French)" , "room for artist" , "Tie earl up in the artist's place" , "Designer's workshop" , "Artist's workshop, studio" .)