A tyro is a beginner, a new recruit, or someone who is just learning something. If you are the new guy at the job and you're wearing a big dorky badge that says "Trainee" on it, you are a tyro.
Tyro isn't used much these days but it's similar to newbie, novice, or recruit. We have all been tyros at some point, but it doesn't necessarily prevent us from hazing the new kid, the next-generation tyro. Tyro can also be used as an adjective to describe someone new to a particular scene — such as "the tyro congressman" or "the tyro quarterback."