This is the 1667th most frequent Russian word.
польшу
"Польшу" is the accusative form of "Польша," meaning "Poland" in English.
The word 'Польшу' here is the accusative case of 'Польша,' referring to the destination of the travel.
Я поеду в Польшу летом.
I will travel to Poland in the summer.
The word 'Польшу' in this sentence serves as the direct object of the verb 'обсуждали' (discussed).
Мы обсуждали Польшу вчера.
We discussed Poland yesterday.
In this sentence, 'Польшу' functions as the object of the prepositional phrase 'про Польшу' (about Poland).