kaathi
A person who is like a nice cake one day and then turns into a pile of vomit the next.
My friend is a kaathi. He said he'd come to my birthday. Then he didn't show up and sent me a message saying 'I had to do my taxes.'
My teacher is a kaathi. She said I was doing well. Then she gave me a pop quiz and failed me.
My cat is a kaathi. He purrs like a angel. Then he knocks over my coffee and runs away.