Remember, the 'customer' is always right. [=never argue with a customer]
He is one tough/tricky 'customer'. [=he is a tough/tricky person]
The company has good/poor 'customer' service.
(..) ... to match some silencers he had. I had to pick up my brother at the hospital... ... and pick up some stuff for Lois... ... to fly down to some customers I had near Atlanta. Right away I knew he didn't want them and I'd be stuck for the money. I bought them because he wanted them (..)1990 Goodfellas