rookie

An inexperienced recruit, especially in the police or armed forces.

A novice.

An athlete either new to the sport or to a team or in his/her first year of professional competition, especially said of baseball, basketball, hockey and American football players.

A type of firecracker, used by farmers to scare rooks.

Non-professional; amateur

The game was going well until I made that rookie mistake.

the rookiest of rookie mistakes

To be a rookie; to go through one's inexperienced learning period in a job, team, or organization.

In 1977 he rookied as a smokejumper with the International Forest Fire Systems, a private firm that contracted smokejumping services to Canada's Northwest Territories.

As they go ton the stretch of road that ran between the park and the 5 Freeway, Stu said 'Schoelkopf gave me the kind of lecture I haven't heard since I rookied. […]'

To haze one or more rookies as an initiation ritual.

Great was my surprise when I found that I had been "rookied" in for a policing-up detail with no chance to "allez."

There is none of that 'rookying stuff' but they don't pay any attention to you either, and that is worse.