The word is new. The act is not. People have been disappearing from each other since people have had each other to disappear from. What is new is the digital context in which it now occurs: a world in which the evidence of another person's continued existence — their social media presence, their last-seen timestamp, their seen receipt — remains visible while their willingness to communicate with you does not. The ghost is not gone. They are present and absent simultaneously, which may be the cruelest form of disappearance.
Clinically, ghosting is a failure of symbolic honesty — and often, though not always, a failure born from overwhelm rather than malice. Most people who ghost do so because they cannot find the words for an ending, because they fear confrontation, because they have no model for how to say I don't want this to continue. This does not make it kind. It makes it a relational act of omission with consequences that fall entirely on the person who is left.
Ghosting says, without saying: Your feelings do not require my management. It is one of the most efficient ways to communicate worthlessness, even when that is not the intention. And it confirms, in the person who is left, something they may have suspected about themselves: that they are too much, or not enough, or simply — most devastatingly of all — easily forgotten.