A general expression of delight that is longer but more enjoyable to use than "yay." Usually reseverd for situations that are not overly common so that the phrase does not become unwieldy.
Friend 1 "Finals are finally over!"

Friend 2 "Yayfullness!"

Random person who just got a new phone "Yayfullness!"

Someone who snagged the last cookie in the school cafeteria "Yayfullness."
by AverageEmi June 8, 2009
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