którego

którego

"Which" or "of which" (genitive case of "który").

The word 'którego' is used here as a relative pronoun referring to a masculine singular noun in the accusative case.

To jest mężczyzna, którego znam.

This is the man whom I know.

'Którego' acts as a relative pronoun referring to a masculine singular noun in the genitive case.

Pokryła wydatek, którego nie przewidziała.

She covered an expense that she had not foreseen.

Here, 'którego' is used as a relative pronoun referring to a masculine singular noun in the accusative case.

Nie znam człowieka, którego spotkałaś.

I don't know the man whom you met.