Mount new art after artist ruined atelier's openings (6)
I believe the answer is:
ararat
'mount' is the definition.
(I've seen this before)
'new art after artist ruined atelier's openings' is the wordplay.
'new' indicates an anagram.
'after' is a charade indicator (letters next to each other).
'openings' says to take the initial letters (I've seen 'opening' mean this).
The initial letters of 'artist ruined ateliers' is 'ara'.
'art' with letters rearranged gives 'rat'.
'rat' put after 'ara' is 'ARARAT'.
(Other definitions for ararat that I've seen before include "Mount (the Ark''s last resting place)" , "Turkish Mount said to contain Noah's Ark" , "Final resting place of Noah's ark" , "Biblical mountains" , "OT mount" .)