Not to be confused with drunk texting, this is texting random friends in the middle of the night when you are stone sober and cannot sleep in the hopes of finding someone else awake to amuse and entertain you. Usually you look like crap because you are exhausted, cannot sleep, so you are a bit scarey.
Unable to sleep Randy picked up his cell phone and zombie texting Luke at 3am to see if he too might be awake.
When someone does or tries to continue a text message conversation that is clearly over and no more needs to be said, most of the time it will be akward and the person is just not getting the hint that the conversaton has ended.
Joe stop zombie texting Kim, u just messaged her 5 mins ago, she said she'll be there now quit texting her already before u make ur self look like an idiot, especially since u just met her.
kind of a shitty exmple but u pretty much get the point of it from the deffinition.