Meaning of “mature” - Learner’s Dictionary

mature

adjective uk us /məˈtjʊər/
AGE

completely grown or developed:

sexually mature
mature trees
BEHAVIOUR

B2 Mature people behave like adults in a way that shows they are well developed emotionally:

She seems very mature for thirteen.
→ Opposite immature

(Definition of “mature adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)