This is the 17385th most frequent Polish word.
zaproszony
"Zaproszony" means "invited" in English.
The word 'zaproszony' is used here as an adjective in the past participle form, indicating a state of having been invited.
Jestem zaproszony na przyjęcie.
I am invited to the party.
'Zaproszony' acts as a past participle used attributively, describing the acquaintance.
Znajomy zaproszony przez Ciebie przyszedł na spotkanie.
The acquaintance invited by you came to the meeting.
In this case, 'zaproszeni' serves as a noun derived from the past participle form, referring to the group of invited people.