Justin [Future RAF Policeman]'s definitions
A sis is a bump which women may get on their breast which is just a build up of fluid but often thought to be a cancerous bump.
My aunti went to the doctors yesturday to see about that bump on her lower breast but it wasnt cancer, it was a sis thank God.
by Justin [Future RAF Policeman] May 5, 2007
Get the sismug.