Translation guide
Expressing that someone is younger in age, or referring to a younger sibling or junior. Japanese uses different words depending on whether you are comparing ages, talking about a younger sibling, or referring to a junior in school or work.
To say that someone is younger than someone else, or to describe a person as young.
A noun meaning 'younger' or 'junior' in age. Commonly used to describe someone who is younger than you or another person.
He is younger than me.
I have many younger friends.
An i-adjective meaning 'young'. Used to describe someone's youth in general, not necessarily in comparison.
Not used directly for 'younger than'; use 年下 for comparisons.
She is still young.
Pattern meaning 'younger than A'. Replace A with the person or thing being compared.
I am younger than my older brother.
Formal or written term meaning 'younger' or 'juvenile'. Often used in official contexts.
younger children
To refer to a younger brother or sister.
Younger brother. Used when talking about your own younger brother to others, or when referring to someone else's younger brother.
My younger brother is a college student.
Younger sister. Same usage as 弟 but for a sister.
Polite form of 弟, used when referring to someone else's younger brother.
How is your younger brother?
Polite form of 妹, used when referring to someone else's younger sister.
To refer to someone who is junior in a school, club, or company hierarchy.
A junior in school, club, or workplace. Implies a hierarchical relationship where the junior is expected to show respect to the senior (先輩).
He is my junior (at work/school).
Can also be used for a younger person in a general sense, not necessarily with the hierarchical nuance of 後輩.
年下 is a noun meaning 'younger (than someone)' and is used for direct age comparison. 若い is an adjective meaning 'young' and describes youth in general. You cannot say '彼は私より若いです' to mean 'He is younger than me' (it sounds like 'He is more youthful than me'). Use 年下 for 'younger than'.
He is younger than me.
He is young.
English speakers often mistakenly say '彼は私より若い' to mean 'He is younger than me'. This is unnatural. Use 年下 instead.
妹は高校生です。
My younger sister is a high school student.
妹さんは何歳ですか。
How old is your younger sister?
I teach work to my junior.
年下の同僚
a younger colleague