A group of kids who just saw their first uncircumcised penis and didn't know what it was so they just called it a Snuffy. Now it is a very popular term.
When someone holds a dooropen for you, gets bored, and stops holding it for you.
-- or --
When someone looks at you and chooses not to hold it open for you.
Wow, that cunt face just shnuffed me.
I can't believe this. The other day, I held that fuckingdoor open for that fucking teacher and they just shnuffed me.