infantilism

American  

[in-fuhn-tl-iz-uhm, -tahy-liz-, in-fan-tl-iz-uhm] / ˈɪn fən tlˌɪz əm, -taɪˌlɪz-, ɪnˈfæn tlˌɪz əm /

noun

1. the persistence in an adult of markedly childish anatomical, physiological, or psychological characteristics.

2. an infantile act, trait, etc., especially in an adult.

3. a speech disorder characterized by speech and voice patterns that are typical of very young children.

---

infantilism British  

/ ɪnˈfæntɪˌlɪzəm /

noun

1. psychol

   1. a condition in which an older child or adult is mentally or physically undeveloped

   2. isolated instances of infantile behaviour in mature persons

2. childish speech; baby talk

---

Etymology

Origin of infantilism

First recorded in 1890–95; infantile + -ism

Example Sentences

It’s a childish move, but in keeping with the infantilism that still shapes the brothers’ uneasy relationship and their awkwardness with outsiders, particularly women.

From New York Times • Nov. 30, 2021

On the other hand, the urgency, almost the desperation, to return feels like a microcosm of our national infantilism when faced with the need for self-discipline and deferred or denied gratification.

From Washington Post • Jul. 24, 2020

Not even Tolkien’s vast philological scholarship, his deep knowledge of mythology, and his world-building skills could impress what Moorcock and company saw as a troublesome infantilism inherent in Tolkien’s work.

From The New Yorker • Dec. 31, 2014

Even my son’s embarrassed by the infantilism of my tastes, but there’s some good stuff out there now.

From The Guardian • Oct. 25, 2014

In either case there is also an infantilism, a retention of the infantile mental traits, a lack of development of the adult mental attitudes and reactions.

From The Glands Regulating Personality by Berman, Louis, M.D.

Related Words

• ignorance
• imperfection