infantile

1 of 2

adjective

in·​fan·​tile ˈin-fən-ˌtī(-ə)l  -tᵊl  -ˌtēl  -(ˌ)til 

1

: of or relating to infants or infancy

2

: suitable to or characteristic of an infant

especially : very immature

infantile humor

infantility

ˌin-fən-ˈti-lə-tē 

noun

infantility

2 of 2

noun

in·​fan·​til·​i·​ty ˌinfən‧ˈtilətē 

plural -es

: the quality or state of being infantile : childishness

Synonyms of infantile

Adjective

• childish
• immature
• adolescent
• juvenile

Examples of infantile in a Sentence

Adjective

the infantile humor that teenage boys are justly famous for

Recent Examples on the Web

Adjective

Miami’s infantile offense can’t afford to carry this team. —Omar Kelly, Miami Herald, 12 June 2026

That now seemed an infantile idea. —Chang-Rae Lee, New Yorker, 3 May 2026

Not for infantile name calling. —Mike Fleming Jr, Deadline, 8 Apr. 2026

Among them was a treatment option for infantile hypophosphatasia, a rare form of rickets that makes children’s bones dangerously fragile. —Ashley MacKin Solomon, San Diego Union-Tribune, 27 Feb. 2026

Word History

Etymology

Noun

Medieval Latin infantilitas, from Latin infantilis infantile + -itas- -ity

First Known Use

Adjective

1696, in the meaning defined at sense 1

Phrases Containing infantile

• infantile paralysis

Kids Definition

infantile

adjective

in·​fan·​tile ˈin-fən-ˌtīl 

-tᵊl, 

-ˌtēl

: of, relating to, or resembling infants or infancy

also : childish

Medical Definition

infantile

adjective

in·​fan·​tile ˈin-fən-ˌtīl  -tᵊl  -ˌtēl  -(ˌ)til 

1

: of, relating to, or occurring in infants or infancy

infantile eczema

2

: suitable to or characteristic of an infant

especially : very immature