great-nibling-in-law
1. The grandchild-in-law of one's sibling.
2. The grandchild of one's spouse's sibling.
2. The grandchild of one's spouse's sibling.
My great-nibling-in-law is a good person.
co-great-nibling-in-law
The grandchild-in-law of one's spouse's sibling.
My co-great-nibling-in-law is a good person.