This is the 13649th most frequent Spanish word.
retrasado
"Retrasado" means "delayed" or "behind schedule" in English.
In this sentence, 'retrasado' is used as an adjective to indicate that the train's schedule is not on time.
El tren está retrasado.
The train is delayed.
Here, 'retrasado' is employed to describe a situation where something (development) is occurring later than typically expected for the person's age.
Él tiene un desarrollo retrasado para su edad.
He has a delayed development for his age.
In this case, 'retrasado' describes someone's state of being late to an event or commitment.