A bantamweight is a boxer who weighs between 51 and 53.5 kilograms, or a wrestler who weighs between 52 and 57 kilograms. A bantamweight is heavier than a flyweight but lighter than a featherweight. the European bantamweight title-holder. a boxer who weighs less than 53.52 kilograms, and who is heavier than a flyweight but lighter than a featherweight