What is Lightweight?

Lightweight definition and meaning on Dictionary terms:
light in weight.
being lighter in weight, texture, etc., than another item or object of identical use, quality, or function: a lightweight topcoat; a lightweight alloy for ship construction.
without seriousness of purpose; trivial or trifling: lightweight reading.
of or relating to a lightweight: He’s the new lightweight contender.

(of a horse, especially a hunter) able to carry up to 165 pounds (75 kg).

a person of less than average weight.
Informal. a person who is of little influence, importance, or effect.

a boxer or other contestant intermediate in weight between a featherweight and a welterweight, especially a professional boxer weighing between 126 and 135 pounds (56.7