This is the 47th most frequent Polish word.
którzy
"Którzy" means "who" or "which" (plural, masculine or mixed-gender) used to refer to people or things.
'którzy' refers to 'ludzie' (people), functioning as a relative pronoun for the masculine plural subject of the subordinate clause.
Ludzie, którzy pracowali cały dzień, zasługują na odpoczynek.
People who worked all day deserve a rest.
'którzy' refers to 'uczniowie' (students), functioning as a relative pronoun for the masculine plural subject of the subordinate clause.
Uczniowie, którzy czytali książki, dostali dodatkowe punkty.
Students who read books received extra points.
'którzy' refers to 'sportowcy' (athletes), functioning as a relative pronoun for the masculine plural subject of the subordinate clause.