Sinatra could be a skilled worker (7)
I believe the answer is:
artisan
'a skilled worker' is the definition.
(an artisan is a skilled craftsperson)
'sinatra could be' is the wordplay.
'could be' indicates anagramming the letters.
'sinatra' is an anagram of 'ARTISAN'.
(Other definitions for artisan that I've seen before include "one in command of craft?" , "Egypt peninsula; holy Mount" , "Skilled manual 17" , "Technician" , "Smith" .)