A blood relative, especially a male. (Dictionary.com)
A relative by marriage. (Dictionary.com)
A person of the same nationality or ethnic group. (Dictionary.com)
A man who belongs to the same family as someone else. (Cambridge)
(in anthropological or formal use) a man who is one of a person’s blood relations. (Oxford Dictionaries)
Someone’s kinsman is their male relative. (Collins Dictionary)
Kinsman twins seek the Cal Poly college experience.