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.

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

Other Word Forms

• infantility 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

If “democracy” has all along been nothing more than a scam rigged to benefit the powerful, then the solution lies in blatant, shameless and overtly infantile version of one-man rule.

From Salon

But lately, more disturbing procedures are on the rise - chasing an unrealistic, hyper-feminine, almost infantile ideal.

From BBC

As O’Toole also observes, Trump’s anti-European animus has a potent psychosexual subtext, simultaneously rooted in right-wing American macho posturing and his own infantile sense of narcissistic injury.

From Salon

“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

Related Words

• childish 
• sophomoric