underdeveloped

American  

[uhn-der-di-vel-uhpt] / ˌʌn dər dɪˈvɛl əpt /

adjective

1. improperly or insufficiently developed.

2. Photography. (of a negative) less developed than is normal, so as to produce a relatively dark positive lacking in contrast.

3. developing.

---

underdeveloped British  

/ ˌʌndədɪˈvɛləpt /

adjective

1. immature or undersized

2. relating to societies in which both the surplus capital and the social organization necessary to advance are lacking

3. photog (of a film, plate, or print) processed in developer for less than the required time, thus lacking in contrast

---

Etymology

Origin of underdeveloped

First recorded in 1890–95; under- + develop + -ed ²

Example Sentences

It can however be fatal to infants with underdeveloped immune systems.

From BBC • Apr. 1, 2026

While much of “Fatherland” feels underdeveloped, it is to Ms. Shorr’s credit that she has let Martin remain a disturbing enigma.

From The Wall Street Journal • Mar. 26, 2026

According to her Instagram post, Phillips was born with an underdeveloped kidney.

From Los Angeles Times • Feb. 11, 2026

Brazil tilts more toward financials and commodities—it is one of the world’s major sources of iron ore, and has vast, underdeveloped rare-earth deposits.

From Barron's • Feb. 6, 2026

And what force would be stronger than me and my admittedly underdeveloped upper- body muscles wailing on the trunk with random tools?

From "Miss Peregrine's Home for Peculiar Children" by Ransom Riggs

Related Words

• embryonic
• nascent
• undeveloped