Great-great-great-great-great-great-great-great-grandnephew.
My 9X-grandnephew is a good person.
by N8953SW June 26, 2021
Get the 9X-grandnephewmug. 
The grandson-in-law of one's spouse's sibling.
My co-grandnephew-in-law is a good person.
by Elivaldeq November 24, 2019
Get the co-grandnephew-in-lawmug.