This is the 9823rd most frequent Russian word.
ястремскую
The word "ястремскую" appears to be a form of a Russian surname, likely referring to "Ястремская" (Yastremskaya), which is a proper noun and does not have a direct definition in English. It would refer to something or someone associated with the surname Yastremskaya.
The word 'ястребскую' is used as an adjective modifying 'книгу', and reflects an association or thematic link to hawks.
Я нашёл ястребскую книгу на книжной ярмарке.
I found the book about hawks at the book fair.
In this sentence, 'ястребском' is the prepositional form of 'ястребский', referring to an experience thematically linked to hawks.
Моя соседка рассказала о своём ястребском походе.
My neighbor talked about her hawk-centered hike.
Here, 'ястребской' is used as an adjective describing the noun 'газеты' (newspaper), implying the newspaper might be about hawks or related topics.