When someone on Facebook comments on a picture or status update well after the thread has long been considered dead, buried, and put to sleep. Facelaggingers are easily spotted by total disregard of conventional time or space constraints. Birthdays from 5 years ago, "Happy bday!" Girlfriend you already broke up with, "cute picture!" Trip you went on in college, with you now married with kids, "OMG you were in Italy!? call me."

Facebaiters often are facelaggers, but they are two very distinct disorders of the social mind.
Amy just pulled some serious facelagging on my high school graduation picture, did she just get back from the future with Marty Mcfly?
by DrSm00th November 10, 2010
Get the Facelagging mug.
The facial sensation one experiences while drunk; sloshy cheeks, tingly lips, and heavy eyelids are all components of facelag.
Guy 1: Bro, I have the gnarliest facelag right now. I swear if you slapped me with a fish it wouldn't even phase me.

Guy 2: I know homie you killed that 40 mad quick. I guess this is why they call it getting shitfaced.
by FuggaDuck October 17, 2011
Get the Facelag mug.
When someone responds to an old status update on Facebook, days or weeks after the date of posting.

Also known as Twitlag.
"John finally responded to my comment about the 2008 elections. The dude has some serious Facelag."
by Joshua 'Z' Hernandez April 1, 2009
Get the facelag mug.