what does it mean when your car just cuts off

It means that you are having an engine performance concern that is coming from a fault in either your fuel, ignition or air intake system, or even because of a restriction in your exhaust system. You have to check to see what is going on by doing proper testing of each area. I can guess that you could have a fuel system issue or a fuel pump issue, but this is a groundless guess not knowing any test results.