Green’s Dictionary of Slang

abfab adj.

[abbr. of absolutely fabulous; the sl. predates the hit UK TV show of the 1990s]

(orig. Aus. teen) a general term of approval, first-rate, very attractive.

[Aus]W. Dick Bunch of Ratbags 217: This worked quite effectively and they then looked real ‘abfab’ (absolutely fabulous), another of our bodgie words. There was a terrific pull-over that had just come out lately from Sydney and boy, was this abfab!
[NZ]McGill Dict. of Kiwi Sl. 9/1: ab-fab extreme enjoyment, short for ‘absolutely fabulous’. Teen jargon 1950s and 1960s. NZA .
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].
K. Cochran DIY Bride Crafty Countdown 18: Upcycle your ab fab Crafty Countdown wedding crafts, so you’ve got good vibes around at all times.