A fork of Rural Dictionary
Someone you know who used to live right next to you.
Tim (to Alex): What's up? Tom (to Tim): Do you even know that dude? Tim (to Tom): Heck yes, he's my ex-door neighbor, we used to hang out sometimes.
The person who used to be, but is no longer your next door neighbor.
I invited my ex-door neighbor from California; I hope you don't mind.
The person who used to live next door to you, but no longer does, either because they moved away or you did.
Susie just moved away, I guess that makes her my ex-door neighbor.