(おとな)びる

おとなびる
ichidan verb
to look/act mature, to seem grown-up
1. to look or act mature, to seem grown-up
Describes a young person whose appearance, behavior, or manner seems older or more mature than their actual age. Can apply to physical appearance, speech, or demeanor.
大人(おとな)びた表情(ひょうじょう)をしている。
She has a mature expression on her face.
あの()(おな)(とし)()より大人(おとな)びて()える。
That child looks more mature than kids the same age.
(ひさ)しぶりに()った(めい)は、すっかり大人(おとな)びた(はな)(かた)をするようになっていた。
My niece, whom I hadn't seen in a while, had come to speak in a very grown-up way.

大人(おとな)びる is an intransitive verb most commonly used in the past participle form 大人(おとな)びた as a modifier.

TRANSITIVITY:

  • Type: 自動詞(じどうし) (intransitive)
  • Pattern: [person]が大人(おとな)びる

COMMON PATTERNS:

  • 大人(おとな)びた(かお): a mature-looking face
  • 大人(おとな)びた(はな)(かた): a grown-up way of speaking
  • 大人(おとな)びた雰囲気(ふんいき): a mature atmosphere/aura
  • 大人(おとな)びて()える: to look mature

The word carries a generally positive or neutral connotation, suggesting poise or composure beyond one's years. It is primarily used about children or teenagers, not about adults.