This is the 2969th most frequent Turkish word.
ukraynalı
Ukrainian (a person from Ukraine).
Here, 'Ukraynalı' is used as an adjective modifying 'yazar' (author) to specify their nationality.
Ukraynalı önemli bir yazar bugün İstanbul'a geliyor.
An important Ukrainian author is coming to Istanbul today.
In this sentence, 'Ukraynalı' is used as a noun representing a person's nationality.
Tanıştığımıza memnun oldum, ben de bir Ukraynalıyım.
Nice to meet you, I am also a Ukrainian.
'Ukraynalılar' is the plural form of 'Ukraynalı', used here to refer to a group of people belonging to the Ukrainian nationality.