adj. (common).A generic intensitive: of pleasure or admiration: used for anything or anybody out of the common: e.g., a SPIFFING TIME or GIRL; awfully SPIFF; How SPIFF you look; How are you? Pretty SPIFF; and so forth. Also SPIFF, subs. = a swell.
1891. LEHMANN, Harry Fludyer at Cambridge, 119. Pat of course looked as if he had just walked out of a ban-box, and the Mater and the girls looked SPIFFING.
2. (drapers).In pl. = a percentage on the sale of old or dead stock.