When ones cell phone has no signal at all and the cell phone shows no bars.
On some cell phones it comes up as a flat line instead of bars or an x.
May be used as Flatline, Flatlined, or Flatlining to describe having no cell reception.
Dude 1: Dude, Where is this party?
Dude 2: Idk, call Sarah.
Dude 1: I can't I'm Flatlining.
Girl: Why the hell didn't you call me back last night?
Boy: Sorry babe, I had a Flatline.
When someone seems to have a serious lack of understanding with anything that either plugs into a power socket or runs on batteries. Mainly Computers and Cell Phones
Son: Hey Ma, Can you check the movie times I'm gonna try and get a quick shower.
Mom: Uhh, How do I do that again?
Son: Go to "Moviefone" and type in Jonah Hex.
Mom: I got some porn site
Son: Goddammit ma, why are you so Tech Retarded?
Big D: Hey man, Do you have Bre's number?
Big C: I think so, How do I pull it up?
Big D: What you never put someones number in your phone before?
Big C: I always just let them do it.
Big D: It's in contacts you Tech Retarded Son of a Bitch!