This is the 1280th most frequent Polish word.
imprezie
"Imprezie" means "party" or "event" in the dative form in Polish.
The word "imprezie" is used as a locative noun in this sentence to indicate the location where the action occurred, i.e., at a party.
Bawiłem się świetnie na wczorajszej imprezie.
I had a great time at yesterday's party.
Here, "imprezie" in the locative case describes the place where people were gathered.
Na imprezie było dużo ludzi.
There were lots of people at the party.
The noun "imprezie" in this sentence demonstrates its use as a subject in temporal anticipation for an event.