This is the 723rd most frequent Polish word.
profilu
"Profilu" is the genitive or locative singular form of "profil," meaning "profile" in English.
Here, 'profilu' is the singular genitive case of 'profil', used after 'swojego' to indicate possession.
Każdy użytkownik serwisu ma możliwość edycji swojego profilu.
Each user of the service has the ability to edit their profile.
In this sentence, 'profilu' is in the singular genitive case and follows 'zabezpieczenia', which is a noun that takes its object in the genitive.
Brak odpowiedniego zabezpieczenia profilu może prowadzić do problemów.
Lack of proper profile protection can lead to issues.
Here, 'profilu' appears in the singular genitive case, required by the action of 'stworzenie' (creation/noun).