Fear of having an unknown person in your backseat (Doesn't matter where you are sitting, the person could be in the trunk for all you know)

Fear of a Killer in the backseat.
Larry: Have you seen the way Rob has been driving lately?
You: Yeah how he just heard about the story of the killer in the backseat.
Larry : Sounds to me like he has a case of extraserophobia
You: Poor guy, hes always checking in the backseat while driving hahaha
by Bobofosho January 13, 2012

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×