Snowpity

The very essence of a mare pony, similar to their soul, but something so profound that transcends such a mundane term and thus necessitates its own word.

Just a stupid in-joke that people on the /mlp/ board on 4chan say. It's meant to be an anti-joke, with the idea that people will ask "What's a snowpity?" just to find out it's a nonword that doesn't make sense and that the joke is it doesn't make sense.