Sinatra performing is skilled at his work (7)
I believe the answer is:
artisan
'skilled at his work' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'sinatra performing' is the wordplay.
'performing' indicates anagramming the letters.
'sinatra' with letters rearranged gives 'ARTISAN'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for artisan that I've seen before include "Smith" , "Egypt peninsula; holy Mount" , "Technician" , "crafty person?" , "Skilled tradesman" .)