This is the 11904th most frequent Polish word.
księża
"Priests."
Here, 'księża' is in the plural nominative case and refers to priests collectively who perform the action of teaching religion.
Księża uczą religii w szkole.
Priests teach religion at school.
In this sentence, 'księży' is in the plural accusative case, serving as the direct object of the verb 'widzę' (I see). It means priests.
Widzę księży na ulicy.
I see priests on the street.
Here, 'księżach' is in the plural locative case, used after the preposition 'o' (about), referring to the topic of conversation—priests.