To "disappear" by not calling, texting, or talking to a certain person. "Going ghost" is a move typically used by friends w/ benefits or booty calls when they no longer want to associate with the other person, but it can also describe a friend you haven't heard from in a long time.
To "go ghost" can also be described as "fading out."
Girl 1: "Have you seen Jordan lately?"
Girl 2: "Nah, he went ghost on me all of a sudden!"
Boy 1: "Jamal, where you been? I see you tryna go ghost on me son!"
Boy 2: "I just been busy, you know you my boy!"
To go ghost means to disappear, either to turn into a ghost or disappear from somebody’s sight, or even his life. It has many other meanings that have to do with sensual activity or suicide.
Another phrase that means "kill yourself". Made popular after Randy Stair aka Andrew Blaze killed 3 people and himself in a supermarket. Besides being a brony, he was also a very avid fan of Ember McLain from the show "Danny Phantom".