This is the 1396th most frequent Dutch word.
volwassen
Mature; adult.
In this sentence, "volwassen" is used as an adjective to describe the state of being an adult, often concerning maturity or age.
De kinderen zijn bijna volwassen.
The children are almost adults.
Here "volwassen" is used as an adverb to indicate behaving in a mature or responsible manner.
Om deze situatie op te lossen, moeten we volwassen reageren.
To resolve this situation, we need to respond in a mature way.
"Volwassen" here functions as a verb (part of the phrase "volwassen wordt") referring to the process of becoming an adult or maturing.