This is the 7867th most frequent Polish word.
mikołajczyk
"Mikołajczyk" is a Polish surname derived from "Mikołaj," meaning "Nicholas."
Here, 'Mikołajczyk' is used as a proper noun referring to a historical figure, Stanisław Mikołajczyk.
Mikołajczyk był polskim politykiem i jednym z przywódców Stronnictwa Ludowego.
Mikołajczyk was a Polish politician and one of the leaders of the People's Party.
In this sentence, 'Mikołajczyk' is used as a proper noun, possibly a surname of a person.
Czy znasz jakiegoś Mikołajczyka, który mieszka w tej okolicy?
Do you know any Mikołajczyk who lives in this area?
Here, 'Mikołajczyk' is likely referring again to Stanisław Mikołajczyk, being used symbolically as an important figure in posters.