This is the 1143rd most frequent Turkish word.
kazanan
Winner.
Here, 'kazanan' is used as a noun meaning 'the winner', referring to a person who succeeds.
Kazanan her zaman doğru karar veren kişidir.
The winner is always the one who makes the right decisions.
In this case, 'kazanan' is used as an adjective describing 'taraf' (side), indicating the side which was successful.
Projeyi zamanında teslim ederek kazanan taraf oldular.
By delivering the project on time, they became the winning side.
Here, 'kazanan' is used as a noun in the possessive form, referring to the person who won the marathon.