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.
(..) what that is. It's illegal and she's pulling your leg. We'd make a lot of money. So could opening our own professional assassin service, but that's not gonna happen either. Why not? I think I'd like that. We could steal (..)2005 TvShow: Six Feet Under Title: Everyone's Waiting Season: 5 Episode 12