This is the 428th most frequent Polish word.
klientów
"Klientów" means "clients" or "customers" (genitive plural form).
Here, 'klientów' is used in its genitive plural form to indicate the customers being counted or referred to.
Liczba klientów w sklepie wzrosła.
The number of customers in the store has increased.
In this sentence, 'klientów' is in the genitive plural form used to show possession or association — the satisfaction belonging to the customers.
Zadowolenie klientów jest dla nas najważniejsze.
The satisfaction of the customers is the most important thing for us.
Here, 'klientów' is in the genitive plural form used to express relations — the loyalty belonging to the customers.