This is the 249th most frequent Ukrainian word.
якій
"Якій" means "which" or "that" (used as a relative pronoun).
The word 'якій' is the dative feminine singular form of the pronoun 'який', used here to indicate the indirect object (the book) in the action of giving.
Це книга, якій я подарував закладку.
This is the book to which I gave a bookmark.
The word 'якій' is in the prepositional feminine singular form, used to describe the internal characteristic (exhibiting talent) of the girl referenced.
Дівчина, в якій я побачив талант, тепер відомий художник.
The girl in whom I saw talent is now a famous artist.
The word 'якій' adapts to the prepositional feminine singular form within the phrase indicating the context or point of focus during an action.