This is the 413th most frequent Polish word.
zagranicznych
"Zagranicznych" means "foreign" or "of/from abroad" (plural genitive or plural accusative form in Polish).
In this sentence, 'zagranicznych' describes 'authors', specifying that they are from foreign countries.
Czytasz książki zagranicznych autorów.
You read books by foreign authors.
Here, 'zagranicznych' modifies 'students', indicating their foreign origin.
Lubię poznawać zagranicznych studentów.
I like meeting foreign students.
In this sentence, 'zagranicznych' refers to 'diplomats', emphasizing their foreign status.