Citação:
Rookie is a term (mainly in North American usage) for a person who is in their first year of play of their sport and has little or no professional experience.
In both North America and the rest of the English-speaking world, the term also has the more general meaning of anyone new to a profession, training or activity (e.g. rookie cop, rookie pilot, as a synonym for recruit), or occasionally to a freshman (especially in athletic teams).
Rookies (in the sporting sense) can be submitted to hazing as a pledge in some clubs.
The term rookie has been modified in some online communities and is often referred to as simply rook, which means noob or newbie.
Fonte: Wikipedia, A enciclopédia livre