Conversation cul de sac 

A conversation cul de sac is the term used to describe the annoying and/or awkward situation that stupid people end up in when talking to a much smarter person. You can subsequently describe either the person or the situation as conversation a cul de sac.

Example 1
As a personal description
"Hey Dan, you meet Gemma the other night? She's is a total conversation cul de sac - every time you try and talk about current events, travel or something else interesting, she manages to make reference to E channel, the Kardashians or Grey's Anatomy."

OR as a situation description
"Hey Dan, I walked into a total conversation cul de sac talking to Gemma last night about the fucking E channel, the Kardashians or Grey's Anatomy."

Example 2
As a personal description
"Hey Jess, you talk to Roger last night? He's a total conversation cul de sac - he just can't seem to hold a conversation on anything other than basketball. For fuck's sake the season's not for three more months - he's so annoying!

OR as a situation description
"Hey Jess, I felt like I was watching a VHS that kept rewinding after 30s last night talking to Roger. It's like walking into a conversation cul de sac over and over again with that guy."

Conversation cul de sac by Springbok27 September 7, 2013