Irrelevant relatives. People in your family who you don't know and hardly ever see, who annoy you at family reunions. They never attend any other gathering that you are aware of. Their sole purpose of turning up to the reunion is to tell you that (unfortunately), you are related to them.
I was at a family reunion last week and one of my irrelatives there just wouldn't shut up about how much weight she'd lost.
1- Collateral relative's spouse's ascendant.
2- Collateral relative's spouse's collateral relative.
3- Descendant's spouse's ascendant. Except in the case of the child-in-law's parent, who is the co-parent-in-law.
4- Descendant's spouse's collateral relative.
5- Spouse's collateral relative's spouse's ascendant.
6- Spouse's collateral relative's spouse's collateral relative.
7- Absence of any type of kinship.