This is a un-common word that is outdated.it's a fancy way to pronounce "fabulous" .Originating in french means "wonderful" or "fantastic" Also an old slang word for the children in the 17th century.Nowadays it's not used anymore.although EditZP is the first ever say it in a Minecraft Video on October 3rd.
"Fantaboulate..Fantaboulate? That should be a real word..That SHOULD be a word! I demand somebody to put that in the dictionary.."
"that was Fantaboulate!"
"Isn't Fantaboulate really a word?"