underdeveloped

adjective

un·​der·​de·​vel·​oped ˌən-dər-di-ˈve-ləpt 

1

: not normally or adequately developed

underdeveloped muscles

underdeveloped film

2

: having a relatively low economic level of industrial production and standard of living (as from lack of capital)

underdeveloped nations

underdevelopment

ˌən-dər-di-ˈve-ləp-mənt 

noun

Examples of underdeveloped in a Sentence

The baby was born with underdeveloped lungs.

Recent Examples on the Web

Across state and federal lands, accommodations designated for Black Americans were routinely and nakedly inferior, relegated to remote, underdeveloped parcels or mosquito-prone swamplands. — Kimmie Gordon, Chicago Tribune, 22 Aug. 2026

In a Texas hospital this week, doctors performed a complex, high-risk, open-heart surgery on a 6-day-old boy born with hypoplastic left heart syndrome, a rare congenital condition that rendered part of his heart underdeveloped. — Lauren Mascarenhas, CNN Money, 20 Aug. 2026

The movie’s only weak link is an underdeveloped romantic subplot involving CODA’s Emilia Jones. — The Week Us, TheWeek, 17 Aug. 2026

West, who is from Alaska, was about 20 weeks pregnant when the baby was diagnosed with hypoplastic left heart syndrome, a rare and serious congenital condition where the left side of the heart is underdeveloped, Paxton's office said. — Kerry Breen, CBS News, 12 Aug. 2026

Word History

First Known Use

1892, in the meaning defined at sense 1

Rhymes for underdeveloped

• developed
• enveloped
• redeveloped
• undeveloped

Kids Definition

underdeveloped

adjective

un·​der·​de·​vel·​oped ˌən-dər-di-ˈvel-əpt 

1

: not developed normally or enough

underdeveloped muscles

2

: having a low level of industrial production and standard of living

the underdeveloped nations

Medical Definition

underdeveloped

adjective

un·​der·​de·​vel·​oped ˌən-dər-di-ˈvel-əpt 

: not normally or adequately developed

underdeveloped muscles

underdeveloped lungs