When you are around an adult and cannot say the words “shut the fuck up” but also believe “shut up” is too mainstream.
Imbecile: “Umm, actually, vaccines cause Autism-“
Person With Half A Brain: “Shut face, dumbass.”
another way of saying "no way" or "yeah right"
girl 1:i just won $500
girl 2:shut your face down
girl1:no really,i did
girl 2:thats awesome