Horrid, isn't it.
The horrible thing seems to have been used most often in the 1980s, as in "Don Lane mania is sweeping the city - people simply can't get enough of this fabtastic talent" which is from a piece by James Wolcott.
I suppose the idea is that something fabtastic is even better and more sparkly than something merely fantastic or fabulous.
And is that impression the word gives us?
Nope. It comes over as a lazy attempt to express enthusiasm for something that's too boring to be worth describing properly.
It's not heard often, now, but it's left a faint trail of saccharine horror over the last part of the twentieth century.
Ah well. It's another reason to be grateful for the new millennium, isn't it.
Word Not To Use Today: fabtastic. The words fantastic and fabulous are both to do with make-believe. Unfortunately fabtastic exists in real life. Boo!