A rookie is someone who is new to a job, sport, or activity and still learning how to do it well. When a baseball player joins a major league team for the first time, they're called a rookie, even if they've been playing baseball for years. Police officers in their first year on the job are rookies too. The word suggests you're at the beginning stage, when everything feels unfamiliar and you're still figuring things out.

Rookies often make mistakes that more experienced people wouldn't, simply because they haven't encountered certain situations before. A rookie chess player might miss an obvious trap, while a rookie cook might forget to set a timer. This doesn't mean rookies are incompetent, it just means they're learning.

In sports, teams sometimes have a Rookie of the Year award for the first-year player who performs the best. Being a rookie isn't permanent: with practice and experience, every rookie eventually becomes a veteran. Everyone who's ever been great at anything was once a rookie who kept working until they mastered their craft.