What it means
Caspering is the polite cousin of ghosting, letting someone down gently and fading out with a kind word or two rather than vanishing without a trace. You might send a soft it's not you, it's me before slowly going quiet, so it feels friendlier even though the result is the same. Named after Casper the friendly ghost, it's ghosting with manners.
Usage examples
"He didn't just vanish, he went caspering, a nice message and then slowly less and less contact."
"Caspering still ends with you ghosted, just with a polite note attached."
"She didn't fully ghost me, she sort of did a caspering thing and hit me with a really nice goodbye text first."
"That's not closure, that's caspering with better manners and a smiley face."
Where it comes from
It comes from Casper the Friendly Ghost, the cartoon character with the soft, harmless vibe. The dating slang spin showed up online in the 2010s to name a nicer-looking version of ghosting, where someone gives a sweet little exit text first, then slowly fades into message mist.