Frantabulous is a mix of Fabulous and Fantastic. A girl named Fran made the word fantabulous into her own by adding an r. FRANtabulous. People use it to refer to things that are fashionable and cool. Instead of saying fabulous and fantastic, you say Frantabulous.
Sort of like "fabulous" but much more fabulous than the word "fabulous" can convey. Like supercalifragilisticexpialidocius but shorter and easier to spell.
While on a free trip to Italy I won a free titanium frame bicycle and the customs agent let me bring it on the plane for free. What a Fantabulous trip!
Fantabulous is an adjective meaning something is of the highest quality. It is a combination of fantastic and fabulous, which was commonly used in London in the 1960s and 70s to describe various aspects of pop culture and fashions. It was especially popular with Chelsea girls like Joanna Lumley. It is still in use in England today, but not as much as it used to be.