Forward I am heavy, but backward I am not. What am I?

Why this works

This riddle plays with the concept of reversing letters to create different meanings. When you read "ton" forward, it refers to a large weight, which is indeed heavy. However, when you spell "ton" backward, you get "not," which implies the absence of weight or heaviness. This clever wordplay between "ton" and "not" is what makes the riddle both intriguing and fun!