Ghosting a person means you simply don't respond to any messages or calls in the hopes they will go away.
I highly recommend NOT doing this.
It might be less stressful for YOU but it is extremely stressful for the person who has no idea what is going on. Maybe you're hurt. Maybe your phone is broken. Maybe something is wrong.
Most people in our universe connect with other people in vast networks. Practically none of us lives alone on a desert island. So the way you impact another person isn't just about that one person. There are all sorts of complex ripples which move out from there. If you are in essence seeding your world with negative energy and emotions about you, it's going to come back to cause you trouble.
Just send them a quick message. Apologize and say it wasn't meant to be. You don't have to go into specifics. Just let them know, clearly, it is over.
If they keep harassing you after that, THEN it is fine not to respond. You've made the situation clear and now the conversation is over.
But do send that message so they know your phone is working, you weren't in a car accident, and you're simply not into them.