The combined word of "why" and "what."
Used when you want to ask the above mentioned terms at the same time to save time.
Me: Hey what's up?
You: Oh, nothing, just have this stupid English assignment to do that was popped up at us.
Me: Whyat?
You: The teacher is an asshole and wants more grades for the quarter; the assignment is based on history which is more fucked up.