A classic douchebag move where one party of a conversation drops the entirety of the discussion and leaves completely, most notably without a goodbye.
The most common example of this is seen online where during a conversation someone will inevitably leave the chat and log off without a single warning or hesitation, and not out of frustration or shitty internet connection.
This also applies to real life when speaking to someone either in person or on the phone where they either turn their attention elsewhere or hang up, respectively.
"Dude, way to totally pull a Jordan last night and stop talking to me without saying 'goodbye.' Douche."