1. a first public appearance on a stage, on television, etc.
2. the first appearance of something, as a new product.
3. (of a young woman) a formal introduction and entrance into society, as at an annual ball.
4. the beginning of a profession, career, etc
to appear for the first time, as on the market
A new product will debut next month.
Someone is allowed to participate in a game or sport where the person playing them is significantly better. Usually results in the novice being outplayed or beaten badly.
Lebron James gave Bob his debut yesterday when he dunked on him.
I gave him his debut yesterday when we played poker.