grumpcatin' 

When you are in a bad mood or pissed off.

Why you grumpcatin'?

grumpcatin' by DJ June 14, 2003

grumpadin 

A slang term used to describe someone who is grumpy (picture of a gremlin/goblin/troll comes to mind)

"I hate Dan, he is such a grumpadin."

grumpadin by your mom is here again November 5, 2008