infantile

[ in-fuhn-tahyl, -til ]

adjective

1. characteristic of or befitting an infant; babyish; childish:

   infantile behavior.

   Synonyms: weak, immature, puerile

   Antonyms: mature, adult

2. of or relating to infants or infancy:

   infantile diseases.

3. Physical Geography. youthful ( def 5 ).

infantile

/ ˈɪnfənˌtaɪl; ˌɪnfənˈtɪlɪtɪ /

adjective

1. like a child in action or behaviour; childishly immature; puerile
2. of, relating to, or characteristic of infants or infancy
3. in an early stage of development

Derived Forms

• infantility, noun

Other Words From

• in·fan·til·i·ty [in-f, uh, n-, til, -i-tee], noun

Word History and Origins

Origin of infantile¹

From the Latin word infantīlis, dating back to 1690–1700. See infant, -ile

Synonym Study

See childish.

Example Sentences

NASA’s James Webb Space Telescope’s high resolution, near-infrared look at Herbig-Haro 211 reveals exquisite detail of the outflow of a young star, an infantile analogue of our Sun.

From Salon

It is the parent’s job, as it is the true political leader’s job, to offer an alternative to the infantile animosities that emerge in hard times.

From Slate

“It was offensive and infantile, especially as the moms were all trying to figure out childcare during summer break.”

From Salon

Even as their infantile, often disgusting antics become tedious, the film’s tone shifts from daft to tenderly melancholic as signs of human encroachment on their habitat multiply.

From New York Times

Sometimes, it's sort of the weird maternal, infantile and sexual all combined all at once, like when she's singing “Santa Baby.”

From Salon

Related Words

• childish
• sophomoric