Another word for crazy, loony, loopy, nutty. Somebody who has lost it upstairs.
That old man is yumpy!
by Danny00 November 27, 2007
An adjective describing something (usually an animal or person) that is simultaneously cute and ugly. Yumpiness is often accompanied by the sensation of something being so ugly it's cute.
Wow, Eleanor Abernathy (better known as the crazy cat lady of "The Simpsons"), your new persian cat is so yumpy! I love it.
by Catssandra Mewller July 16, 2012