a blank text message with a pre-determined meaning, used as a quick, convenient way to tell someone something without texting actual words. Often acknowledged or answered with a return blank.
Often used as a phrase: "...shoot me/you/him/her a blank..."
Shoot me a blank when you get here.
I'll shoot you a blank if I like the movie.
Shoot me a blank if you want to go to the show tonight.
Shoot me a blank if you need a ride tomorrow.