Newbies are penguins who are brand new to Club Penguin. They are typically not members, but can be. Newbies know little about how the game works, and are known to go up to older penguins and ask them where they got an item that is not currently available.
Newbies are widely thought of as annoying.
Newbies only have recent clothing items, so this is all they wear. Extremely new players typically wear the new player hat.