Dictionary.com
Thesaurus.com
Synonyms

underweight

American  
[uhn-der-weyt, uhn-der-weyt] / ˈʌn dərˈweɪt, ˈʌn dərˌweɪt /

adjective

  1. weighing less than is usual, required, or proper.

noun

  1. deficiency in weight below a standard or requirement.

underweight British  
/ ˌʌndəˈweɪt /

adjective

  1. weighing less than is average, expected, or healthy

  2. finance

    1. having a lower proportion of one's investments in a particular sector of the market than the size of that sector relative to the total market would suggest

    2. (of a fund etc) disproportionately invested in this way

      pension funds have become underweight of equities
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of underweight

First recorded in 1590–1600; under- + weight

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Boone was underweight, had sore ears and sore eyes when he first came into the RSPCA's care, Murphy explained.

From BBC • Apr. 9, 2026

The largest discrepancy appeared in the underweight group.

From Science Daily • Apr. 3, 2026

A team of strategists at Deutsche Bank said discretionary investors were already clearly underweight stocks, according to their in-house data — although they had room to further reduce their exposure.

From MarketWatch • Mar. 30, 2026

MS has an underweight rating and A$34.40 target price on the stock, which is up 0.65% at A$40.725.

From The Wall Street Journal • Mar. 27, 2026

Despite the extraordinary fineness of his features, and his age, and his general stature—clothed, he could easily have passed for a young, underweight danseur—the cigar was not markedly unbecoming to him.

From "Franny and Zooey" by J. D. Salinger

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.