A newb is someone that is new to a certain industry.
A newb is typically referred to as someone who is inexperienced in a certain thing. This can include someone new to video games, or being new in the world of cryptocurrencies. You can think of a newb as someone who has never used a cryptocurrency exchange throughout their life and is for the very first time experiencing what things are like.
There are other words alongside newb that mean the same thing, such as newbie, noob or nub. This is a slang term for a novice or a newcomer. Contemporary use can particularly refer to a beginner or new user.
At one point in your life, even you were a newb. Before you clicked on this to read it, you were a newb when it came to understanding its meaning, but now you are a pro.
You can think of this word as the meaning behind someone who is genuinely just getting into something new. This can be compared to the word "freshman" in college, which refers to someone who is a first-year student and does not really know what awaits them.