Sinatra confused a skilled worker (7)
I believe the answer is:
artisan
'a skilled worker' is the definition.
(an artisan is a skilled craftsperson)
'sinatra confused' is the wordplay.
'confused' is an anagram indicator.
'sinatra' anagrammed gives 'ARTISAN'.
(Other definitions for artisan that I've seen before include "Crafty sort" , "one in command of craft?" , "Sinatra (anag) -- skilled manual worker" , "crafty person?" , "Handy worker" .)