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un·​der·​weight ˌən-dər-ˈwāt How to pronounce underweight (audio)
: weight below normal, average, or requisite weight


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: weighing less than the normal or requisite amount

Examples of underweight in a Sentence

Adjective the long illness left him frail and underweight
Recent Examples on the Web
Patients with anorexia were still unable to bring themselves to eat, still stuck in rigid thought patterns, still chillingly underweight. Rachel Gutman-Wei, The Atlantic, 7 Sep. 2023 His team remains overweight on the rest of the world, with a focus on Switzerland, while remaining underweight on the US — a strategy that hasn’t yet panned out as the S&P 500 is outperforming the MSCI All-Country World Index excluding the US this year. Farah Elbahrawy, Fortune, 4 Sep. 2023 Rudy Rudy arrived at his forever home underweight and in need of training and is now a healthy, affectionate dog who enjoys making new friends. Kelli Bender, Peoplemag, 25 Aug. 2023 The calf was born slightly underweight and had a hard time nursing, according to zoo officials, concerning animal caretakers and prompting intervention. Miriam Marini, Detroit Free Press, 13 June 2023 Only 6% of folks with eating disorders are clinically underweight (according to BMI standards, which, again, even the American Medical Association admits are deeply flawed). Christine Byrne, Mph, SELF, 28 Aug. 2023 Black and Latino teens are also more likely to struggle with bulimia and binge eating disorder, which can lead to serious cardiac complications and significantly increase suicide risk even in patients who aren’t underweight. Sonja Sharp, Los Angeles Times, 11 Aug. 2023 For managers that are underweight China, the pullback/correction from the past week may provide an opportunity to get back in. Brendan Ahern, Forbes, 6 Feb. 2023 Despite the pervasive eating disorder stereotype — white, female and underweight — teens from racial and ethnic minority groups, as well as males and teens with larger bodies, develop certain eating disorders at even higher rates, according to research. Caroline Hopkins, NBC News, 29 Apr. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'underweight.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use


1596, in the meaning defined above


1675, in the meaning defined above

Time Traveler
The first known use of underweight was in 1596

Dictionary Entries Near underweight

Cite this Entry

“Underweight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underweight. Accessed 25 Sep. 2023.

Kids Definition


: weighing less than what is normal, average, or necessary

Medical Definition


un·​der·​weight -ˈwāt How to pronounce underweight (audio)
: weighing less than the normal amount for one's age, height, and build
underweight children
underweight adults typically have a body mass index of less than 18.5
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