This is the 11th most frequent Ukrainian word.
його
"His" or "him."
Here, "його" is a possessive pronoun meaning "his" referring to the book.
Він взяв його книгу зі столу.
He took his book from the table.
Here, "його" functions as an accusative form of "he" meaning "him."
Я бачив його вчора в парку.
I saw him yesterday in the park.
Here, "його" is a possessive pronoun meaning "his" referring to the work.