When Naomi heard about Boaz, she told Ruth he was one of their what?

Answer: Kinsman-redeemers

Naomi said, "The man is a close relative. He is one of our kinsman-redeemers" (KJV: next kinsmen).

“Then Naomi said to her daughter-in-law, “May he be blessed by the LORD, who has not withdrawn His kindness from the living or the dead.” Naomi continued, “The man is a close relative. He is one of our kinsman-redeemers.””— Ruth 2:20 (BSB)