Noun. The kind of viking who is always happy and outgoing, and is often interested in world affairs. Cannot be used to describe similar vikings who may or may not be happy and/or outgoing. The name greasy viking is slightly misleading as many vikings did actually have regular and thorough detox sessions and were relatively clean and pleasant smelling.
Man: "Hey there what can I do for you."
Greasy Viking: "Hi I am a greasy Viking and I am on crack."