Sons flee having pinched a work of art (8)
I believe the answer is:
seascape
'work of art' is the definition.
(seascape is a type of artwork)
'sons flee having pinched a' is the wordplay.
'sons' becomes 's'.
'flee' becomes 'escape' (escaping is a kind of fleeing).
'having pinched' is an insertion indicator.
'escape' placed around 'a' is 'eascape'.
's'+'eascape'='SEASCAPE'
(Other definitions for seascape that I've seen before include "Maritime picture" , "Marine view/picture" , "work of art" , "Painting genre" , "Painting, maybe a Turner" .)