lightweight

American  

[lahyt-weyt] / ˈlaɪtˌweɪt /

adjective

1. light in weight.

2. being lighter in weight, texture, etc., than another item or object of identical use, quality, or function: a lightweight alloy for ship construction.

   a lightweight topcoat;

   a lightweight alloy for ship construction.

3. without seriousness of purpose; trivial or trifling.

   lightweight reading.

4. of or relating to a lightweight.

   He's the new lightweight contender.

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

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noun

1. a person of less than average weight.

2. Informal. a person who is of little influence, importance, or effect.

3. a boxer or other contestant intermediate in weight between a featherweight, and a welterweight, especially a professional boxer weighing between 126 and 135 pounds (56.7–61 kilograms).

lightweight British  

/ ˈlaɪtˌweɪt /

adjective

1. of a relatively light weight

2. not serious; trivial

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noun

1. a person or animal of a relatively light weight

2. 1. a professional boxer weighing 130–135 pounds (59–61 kg)

   2. an amateur boxer weighing 57–60 kg (126–132 pounds)

   3. ( as modifier )

      the lightweight contender

3. a wrestler in a similar weight category (usually 115–126 pounds (52–57 kg))

4. informal a person of little importance or influence

Other Word Forms

• ultralightweight adjective

Etymology

Origin of lightweight

First recorded in 1765–75; light ² + weight

Explanation

When an object is lightweight, it weighs much less than other similar objects. A person is a lightweight if they can't handle much — if you get full after a small meal, big eaters might refer to you as a lightweight. Break lightweight apart — light + weight — and you see its definition right there in its root words. Someone who is called a lightweight is either a professional boxer who weighs under 135 pounds or he's someone with little importance or ability. When a company is looking to make layoffs, it's the lightweight employees, or those who just aren't important to the business that often get axed first.

Example Sentences

This lightweight metal is highly reactive, meaning it can quickly undergo chemical reactions.

From Science Daily • Apr. 16, 2026

Caroline Dubois floored and bloodied Terri Harper before outpointing her British rival to become the unified lightweight world champion at London's Olympia.

From BBC • Apr. 5, 2026

Berlin-based eyewear brand Mykita kick-starts a sunglasses spring with new minimalist lens shapes and ultra-slender lightweight frames.

From Los Angeles Times • Apr. 3, 2026

Each trailer uses about 4,500 pounds of the lightweight metal, which is also its biggest cost center.

From The Wall Street Journal • Apr. 2, 2026

They’d brought lightweight Polartec jackets with their supplies, so they bundled up against the cold rain and walked for a few blocks through the mostly deserted streets.

From "The Son of Neptune" by Rick Riordan