This is the 7614th most frequent Polish word.
legię
"Legię" is the accusative form of the Polish word "Legia," referring to "Legia" (typically the Warsaw football club).
Here, 'Legii' is used in the locative case to refer to the Polish sports club Legia Warsaw, indicating association.
Kibicuję Legii Warszawa, bo to mój ulubiony klub.
I support Legia Warsaw because it is my favorite club.
In this context, 'Legii' is in the genitive case, showing possession or relation to the victory.
Czy widziałeś ostatnie zwycięstwo Legii w meczu?
Did you see Legia's latest victory in the match?
Here, 'Legii' is used in the genitive case to indicate the entity (Legia Warsaw) that the speaker is a fan of.