This is the 1192nd most frequent Polish word.
łukasza
"Łukasza" is the genitive or accusative form of "Łukasz," a Polish male given name equivalent to "Luke" in English.
'Łukasza' is used here as the accusative case of the proper noun 'Łukasz', indicating the direct object of the verb 'widzę' (I see).
Widzę Łukasza na ulicy.
I see Łukasz on the street.
Here, 'Łukaszowi' is the dative case of 'Łukasz', used to indicate the indirect object of the sentence.
Daj książkę Łukaszowi.
Give the book to Łukasz.
In this example, 'Łukasza' is in the genitive case to indicate possession, showing that the keys belong to Łukasz.