1. A type of tie style worn by dorky schoolchildren in the 70s and 80s which is short and fat. In the 21st century, it has become a symbol of the wearer's 'rudeness' and their tendancy to ignore school dress code, what with being too stupid to come up with another, more inventive way to disobey the school rules.
2. A twat who is also fat.
1. Chav 1: Hey, look at me, my tie is only just below the knot!
Chav 2: Wow! You must be really hard to risk being stopped in the corridor and forced to do your tie up like a normal human being. You are now the most popular person in the class. Let's go pick on some intelligent, normal children because they don't wear the latest Nike© Total 180 trainers.
2. Me: Miles, you fat twat.
Miles: About! Shut up! Don't make me come and beat you up.
Me: Yeah, right.