French artist entertained by diplomat is Seurat (7)
I believe the answer is:
matisse
'french artist' is the definition.
(I've seen this before)
'entertained by diplomat is seurat' is the wordplay.
'entertained by' indicates a hidden word (the clue hosts or entertains the answer).
'MATISSE' can be found hidden inside 'diplomat is seurat'.
(Other definitions for matisse that I've seen before include "Henri -, C twenty Fr. painter, sculptor, illustrator" , "Mae sits badly for the French painter" , "French painter, d. 1954" , "Henri ---, Twentieth Century painter" , "Henri -, nineteenth-twentieth century French painter/sculptor" .)