The granddaughter-in-law of one's spouse's sibling.
My co-grandniece-in-law is a good person.
by Elivaldeq November 24, 2019
Get the co-grandniece-in-lawmug. 
Get the co-grandniece-in-lawmug. My great-great-grandniece-in-law is a good person.
by Wonbig October 13, 2021
Get the great-great-grandniece-in-lawmug. Spouse's grandnibling's wife.
My grandniece-by-marriage-in-law is a good person.
by NSBC968755 February 25, 2023
Get the grandniece-by-marriage-in-lawmug. Spouse's great-great-grandnephew's wife.
My co-great-great-grandniece-in-law is a good person.
by JAMP12 September 21, 2021
Get the co-great-great-grandniece-in-lawmug. 
Get the step-co-grandniece-in-lawmug. Spouse's great-grandnephew's wife.
My co-great-grandniece-in-law is a good person.
by JAMP12 September 21, 2021
Get the co-great-grandniece-in-lawmug.