It's "Fab" and "Spectacular" fused together into one word.
Woah. The Beatles are one Fabular band!
by Marlys (Beatle_Soul October 08, 2007
A very homosexualized version of "fabulous". Popular among David Bowie fangirls.
Oh my God, Velvet Goldmine is such a fabular movie!
by Cait the Great December 21, 2004