Used to describe someone that is new to an activity or situation.
Steve: Check out the new weapon I got for Call of Duty. It’s a bazooka!
Johnny: No dude, it’s a newb-tube.
Steve: I smoked you with it, didn’t I?
'Newb' comes from the combination of the words new and boy. When it was originally created, the word was 'newbie'. It has since been shortened to 'newb', and sometimes also written as 'noob'. It is popular among teenagers, video gamers, and software developers in the Aurora area.
Bo Burnham uses the word in his song “Welcome to YouTube”. He says, “YouTube is a place where people come to share their ideas… and if you don’t believe me, you must be a noob”