1853, of uncertain origin, probably related to spiff "well-dressed man." Uncertain relationship to spiff (n.) "percentage allowed by drapers to their young men when they effect sale of old fashioned or undesirable stock" (1859), or to spiflicate "confound, overcome completely," a cant word from 1749 that was "common in the 19th century" [OED], preserved in American English and yielded slang spiflicated "drunk," first recorded in that sense 1902.[spiffy etymology, spiffy origin, 英语词源]