Translation guide
Describes behavior, attitudes, or qualities that are childish in an immature or negative way. Focuses on how to express immaturity, pettiness, or lack of emotional development in Japanese.
To describe someone or something as acting in a way that is immature, petty, or lacking adult emotional control, similar to a child.
To refer to something related to infancy or early childhood, often in medical or psychological contexts.
Means 'of early childhood' or 'infantile' in a clinical sense. Used in phrases like 'infantile amnesia' or 'infantile development'.
幼児期の記憶はほとんどない。
I have almost no infantile memories.
While 幼児 means 'infant' or 'toddler', using 幼児の to describe behavior sounds unnatural. Use 幼稚 or 子供っぽい for immaturity.
His way of thinking is infantile.
そんな幼稚な言い訳はやめてくれ。
Stop making such infantile excuses.
Means 'childish' or 'childlike', but often carries a negative nuance of immaturity when used for adults. Slightly less formal than 幼稚.
彼の行動は子供っぽい。
His behavior is infantile.
Literally 'not adult-like'. Used to criticize someone for lacking maturity or dignity expected of an adult. Very common in spoken Japanese.
そんなことで怒るなんて大人げない。
It's infantile to get angry over something like that.
Means 'immature' or 'unripe'. Can refer to skills, personality, or emotional development. More formal and often used in written contexts.
彼の精神的な未熟さが問題だ。
His emotional immaturity is the problem.
Medical term for 'child' or 'infantile', used in compound words like 小児科 (pediatrics). Can appear in terms like 'infantile paralysis'.
小児麻痺はポリオのことです。
Infantile paralysis is polio.