He's a mere 'amateur' when it comes to cooking. [=he doesn't know how to cook well]
She played soccer as an 'amateur' before turning professional.
These photos were taken by both 'amateurs' and professionals.
(..) No, I'm not. I'm not. So you admit you don't know what you're talkin' about. If you're through givin' me your amateur opinion, lie back and listen. I'm takin' you back to the rendezvous, Joe's gonna get you a doctor... the doctor's gonna fix you up and... you're gonna be okay. (..)1992 Reservoir Dogs