פּירוש אויף רות 2:1

A kinsman. A relative; he was the son of Elimelech’s brother. Our Rabbis of blessed memory said, “Elimelech, and Salmone¹Rus 4:21. the father of Bo’az, and the anonymous kinsman,²Ibid. 4:1. and the father of Naomi,³Therefore Bo’az and Naomi were cousins. were all sons of Nachshon,⁴Shemos 6:23 and Bamidbar 10:14. the son of Aminadav.⁵Maseches Bava Basra 91a. Yet the merit of their fathers was no avail them when they left the Land [of Yisroel] to go abroad.”

A known relative, as in "and understanding you shall call a familiar friend."

Of her husband. From her husband, and here the "lamed" is like in "say he is my brother."

Ivtzan. Boaz.²The husband of Rus, ancestor of King David. (Bava Basra, 91:a)