若い vs 幼い
JLPT N5 vocabulary · what is the difference?
若い means young in age, and is neutral or complimentary for anyone from their teens upwards. 幼い means very young — small-child young — and applied to an adult it is a criticism meaning immature or childish.
When to use each
若い
わかい
Use 若い for anyone young relative to the context: a young teacher, young people, when I was young. Saying someone is 若い is usually a compliment.
先生は若いです。
せんせいはわかいです。
The teacher is young.
若い時にたくさん旅行しました。
わかいときにたくさんりょこうしました。
I travelled a lot when I was young.
幼い
おさない
Use 幼い for small children and early childhood — 幼い子供, 幼い頃. Applied to an adult's behaviour or thinking it means immature, and it is not a compliment.
幼い頃の写真です。
おさないころのしゃしんです。
This is a photo from when I was little.
彼の考えは幼いです。
かれのかんがえはおさないです。
His thinking is immature.
Sentences where only one works
この会社は若い人が多いです。
このかいしゃはわかいひとがおおいです。
This company has a lot of young people.
Adults in their twenties are 若い. 幼い人 would mean toddlers at the office.
幼い子供を公園へ連れて行きます。
おさないこどもをこうえんへつれていきます。
I take my small children to the park.
Pre-school age — 幼い is the natural word. 若い子供 is not used.
三十歳なのに考え方が幼いですね。
さんじゅっさいなのにかんがえかたがおさないですね。
He's thirty but his way of thinking is childish.
Here 幼い is explicitly a criticism; 若い would be a neutral statement of age.
母は年より若く見えます。
はははとしよりわかくみえます。
My mother looks younger than her age.
A compliment about appearance — only 若い works.
Common mistakes
若い子供が公園で遊んでいます。
幼い子供が公園で遊んでいます。
For little children, Japanese says 幼い子供 or 小さい子供. 若い子供 sounds contradictory.
先生はまだ幼いです。
先生はまだ若いです。
Calling an adult 幼い says they are childish, which is an insult, not a comment on their age.
Frequently asked questions
Can I use 幼い as a compliment?
About a child it is simply factual. About an adult, no — it means immature. If you mean someone looks youthful, say 若く見えます.
What about 小さい for children?
小さい子 is the most common casual way to say "little kid". 幼い is slightly more written, and 幼い頃 for "in my childhood" is very common.
Is 若い only for people?
Mostly, but it extends to things with an age-like quality — 若い会社 for a young company, 若い葉 for new leaves. 幼い stays with people and their behaviour.