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

The other infant had Amish microcephaly, a rare and severe genetic disorder that causes a small head and underdeveloped brain and leaves children with little chance of surviving beyond a couple of months, Moss said. — Jen Christensen, CNN Money, 16 Sep. 2026

The girl was born with a condition called Amish lethal microcephaly, which causes an unusually small head and underdeveloped brain. — Mead Gruver, Los Angeles Times, 14 Sep. 2026

The underdeveloped character proved to be the perfect canvas for the early Cartoon Network writers to impose their sensibilities onto. — Christian Zilko, IndieWire, 10 Sep. 2026

She had been born with a condition called Amish lethal microcephaly that causes an unusually small head and underdeveloped brain. — CBS News, 10 Sep. 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