lagger
A lagger is someone who promises to do something and then disappears like a ghost. They’re the worst kind of fake friend.
This lagger said he’d help me move. He showed up with a donkey and left before the boxes were even unpacked.
I asked the lagger to finish my homework. He said he would. He didn’t. I got a D.
This lagger said he’d come to my birthday party. He didn’t show up. I had to eat cake alone.