Sinatra upset craftsman (7)
I believe the answer is:
artisan
'craftsman' is the definition.
('artisan' can be a synonym of 'craftsman')
'sinatra upset' is the wordplay.
'upset' indicates an anagram.
'sinatra' with letters rearranged gives 'ARTISAN'.
(Other definitions for artisan that I've seen before include "craftsman of his trade" , "Skilled worker by hand" , "Train as (anag) - craftsman" , "Mechanic" , "man with skill" .)