To break up with someone, date someone else, act like your going to get back with the first person, and then screwing that person over and sticking with the second person.
Nathan was making-out with Ashley, telling him how much she liked him again, and then double crossed him with her boyfriend Tyler
Synonym for shart. To be double crossed is while trying to expell excess methane from your rectum, you accidently squirt a little pooh out. Double crossing usually happens at the most inconveniant time (see example). After a serious bout of the flu, food poisoning, or dysentary it would be wise not to fart in public.
On his first date with Anne, Bill tried to snap out an innocent little fart and was double crossed. Bill spent the next 20 minutes in the bathroom washing the double cross from his shorts.