Top of the art world? (5)
I believe the answer is:
beret
'top of the art world?' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for beret that I've seen before include "felt on one's head" , "Flattish round hat" , "Frenchman's flat hat" , "French-style hat" , "Basque headgear" .)