(interj.) said when expressing happiness!

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

When yay just wont cut it

The level of yay in a person, place or situation.

when something really really good has happened, instead of saying yay, you say Yayness

showing expressions of great happyness followed by a long list of exclamation marks. usually yelled by some freak who is over excited about something...i.e. what i do, a lot!!!!

Its an expression of joy