adultlike

/əˈdʌltlaɪk/
adjective
  1. Resembling or characteristic of an adult; mature in appearance or behavior.
    • Her adultlike composure during the crisis impressed her teachers.
    • The young actor gave an adultlike performance that earned critical praise.
    • The child's adultlike vocabulary surprised everyone at the dinner table.
Synonyms
What does "adultlike" mean? | whatsthatwordmean | whatsthatwordmean