There are several terms for a new player: n00b/noob/noobie, lowbie, or newb/newbie.
A newbie is the most basic form of a new player; they are simply new to the game. While they may not know the rules or how to play, they're willing to learn. It's sometimes used as an insult, but only by people who forget that everyone starts as a newbie at some point. n00b is a more serious (yet also more ridiculous) insult.