UNDERWEIGHT Synonyms: 57 Similar and Opposite Words

underweight

adjective

Definition of underweight

as in lightweight

having little weight the long illness left him frail and underweight

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of underweight The World Remains Underweight By historical standards, gold investment remains grossly underweight. — Frank Holmes, Forbes.com, 28 July 2026 Experts told the outlets that the eagle did not suffer any broken bones or serious injuries, but had been unable to fly and is underweight. — Kimberlee Speakman, PEOPLE, 21 July 2026 Some pups were weaned early or became underweight, and more than 4,000 young sea lions were found stranded along California beaches during peak years, overwhelming rehabilitation centers. — Brandi D. Addison, USA Today, 2 July 2026 When the 13 siblings were rescued, all but the 2-year-old were severely underweight and hadn’t bathed for months. — ABC News, 2 July 2026 See All Example Sentences for underweight

Recent Examples of Synonyms for underweight

lightweight

Adjective

Developers say the material could reduce the environmental impact associated with conventional floating solar structures while offering a lightweight alternative.

— Neetika Walter, Interesting Engineering, 28 Aug. 2026
The lightweight formula pairs olive, argan, jojoba, sunflower, and safflower oils with smoothing silicones to calm frizz and boost shine.

— Christa Joanna Lee, Allure, 28 Aug. 2026

Definition of lightweight

Browse Nearby Words

under weigh

underweight

underwent

See all Nearby Words

Cite this Entry

Style

“Underweight.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underweight. Accessed 1 Sep. 2026.

Copy Citation

Synonyms of underweight

adjective

Example Sentences

Browse Nearby Words

Cite this Entry

More from Merriam-Webster

Word of the Day

conscientious

Popular in Grammar & Usage

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?

Why does English have so many silent letters?

7 Pairs of Commonly Confused Words

Popular in Wordplay

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

Even More Words That Sound Like Insults But Aren't

Even More Bird Names that Sound Like Insults (and Sometimes Are)

12 Lovely and Unusual Words for the Natural World

Popular

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

Games & Quizzes