This is the 17368th most frequent Polish word.
zapominają
"Zapominają" means "they forget" in English.
Here, 'zapominają' is used as the main verb in the sentence to describe the action of 'forgetting' responsibilities.
Zapominają o swoich obowiązkach.
They forget about their duties.
In this case, 'zapominają' is followed by an infinitive, indicating what the subject is forgetting to do.
Dzieci często zapominają zamknąć drzwi.
Children often forget to close the door.
Here, 'zapominają' introduces a clause explaining the specific thing that is being forgotten by the subject.