This is the 3025th most frequent Polish word.
państwu
"Państwu" means "to you" (formal, plural) in English.
In this context, "państwu" is used as a polite form of 'to you' when addressing a group formally.
Dziękujemy państwu za uwagę.
We thank you all for your attention.
Here, "państwu" implies a formal 'to you' addressing a group in well-wishing.
Życzymy państwu miłego wieczoru.
We wish you all a pleasant evening.
In this case, "państwu" denotes a formal way to address a group receiving the action politely.