: 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
Vanessa Etienne, People.com, 14 July 2025
Not appropriate for all individuals: People who are pregnant, underweight, malnourished, or have a history of disordered eating should avoid the AIP diet.
—Verywell Health, 22 June 2025
In a Facebook post shared on Tuesday, Brother Wolf Animal Rescue shared the story of Alicia, a 1-year-old pup who was found chained outside and severely underweight by a local shelter, and then surrendered to them after testing positive for heartworm.
—Maria Azzurra Volpe, MSNBC Newsweek, 24 May 2025
Paulla King/Paulla King Violet currently weighs just 41.8 pounds—estimated to be 20 to 30 pounds underweight.
—Lydia Patrick, MSNBC Newsweek, 3 July 2025
See All Example Sentences for underweight
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Adjective
Body Mass Index — or BMI — is a formula where a person's weight (in kilograms) is divided by the square of their height (in meters), and that number is used to sort people into four categories: underweight, healthy, overweight or obese.
—Vanessa Etienne, People.com, 14 July 2025
Not appropriate for all individuals: People who are pregnant, underweight, malnourished, or have a history of disordered eating should avoid the AIP diet.
—Verywell Health, 22 June 2025
In a Facebook post shared on Tuesday, Brother Wolf Animal Rescue shared the story of Alicia, a 1-year-old pup who was found chained outside and severely underweight by a local shelter, and then surrendered to them after testing positive for heartworm.
—Maria Azzurra Volpe, MSNBC Newsweek, 24 May 2025
Paulla King/Paulla King Violet currently weighs just 41.8 pounds—estimated to be 20 to 30 pounds underweight.
—Lydia Patrick, MSNBC Newsweek, 3 July 2025
See All Example Sentences for underweight
Cite this Entry
“Underweight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underweight. Accessed 30 Jul. 2025.
Copy CitationMedical Definition
underweight
adjective
un·der·weight
-ˈwāt 
: 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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