He deals with the customers in a very 'professional' way. = He is very 'professional' in dealing with the customers.
a golf/tennis 'professional' [=a skillful golf/tennis player whose job is to teach other people how to play]
I was impressed by the calm and 'professional' way she handled the crisis.
(..) accompaniment today. I guess it's a good thing my mom was an organ donor! What happened to the organ? Why don't you leave the comedy to the professionals? Okay? This is a funeral, sir, for my mother. Can you show a little respect? I'll take it. Beatrice Horseman, who was she? (..)2018 TvShow: BoJack Horseman Title: Free Churro Season: 5 Episode 6