Sinatra, swinging expert (7)
I believe the answer is:
artisan
'expert' is the definition.
(thesaurus)
'sinatra swinging' is the wordplay.
'swinging' indicates an anagram.
'sinatra' is an anagram of 'ARTISAN'.
(Other definitions for artisan that I've seen before include "Sinatra (anag) -- skilled manual worker" , "Skilled manual 17" , "Skilled worker at craft or trade" , "Journeyman" , "Skilled worker by hand" .)