What is the description of Armpit in holes?

In the book Holes by Louis Sachar, Armpit is one of the main characters. He is a large and muscular boy who is overweight. He has a habit of putting his hands in his armpits and sniffing them, which is how he got his nickname. Armpit is not very intelligent and is often teased by the other boys at Camp Green Lake. However, he is also a kind and loyal friend.