The ultra important, high falutin, and just all around annoying sister of your spouse. She will not be at your wedding because she has more important things to do, and if by chance she shows up, she'll ruin it. She's your mother-in-law's teammate and soldier.
The ideal sister-in-law is one that resides six feet below the ground in a cemetery, right next to the ideal mother-in-law.
by Xxxxxxxxfanboyxxxxxxxxxx January 31, 2021
Get the Sister-in-lawmug. 
My sister-in-law ruined my wedding by demanding I pay for her wedding and starting a family fight. Of course my mother-in-law took her side.
by Xxxxxxxxfanboyxxxxxxxxxx November 17, 2020
Get the Sister-in-lawmug.