fabulous Look up fabulous at Dictionary.com
early 15c., from L. fabulosus "celebrated in fable," from fabula (see fable). From "mythical," sense of "incredible" first recorded c.1600. Slang shortening fab first recorded 1957; popularized in reference to The Beatles, c.1963.
"Fabulous (often contracted to fab(s)) and fantastic are also in that long list of words which boys and girls use for a time to express high commendation and then get tired of, such as, to go no farther back than the present century, topping, spiffing, ripping, wizard, super, posh, smashing." [Fowler, 1965]