This is the 13459th most frequent Polish word.
pasierba
"Pasierba" means "stepdaughter" in English.
In this sentence, 'pasierba' refers to a male stepson.
Pasierba odwiedził swoją macochę w jej nowym domu.
The stepson visited his stepmother in her new house.
Here, 'pasierbę' is the female form (accusative case) of 'pasierba', meaning stepdaughter.
Podarowaliśmy pasierbę książkę, którą bardzo polubi.
We gifted the stepdaughter a book she will really enjoy.
In this context, 'pasierba' again refers to a male stepson, but used in a nominative case scenario.