spiffy

adj. well-dressed, elegant, smart; cool (Informal)

Adjective
1. marked by smartness in dress and manners; "a dapper young man"; "a jaunty red hat"
(synonym) dapper, dashing, jaunty, natty, raffish, rakish, smart, snappy, spruce
(similar) fashionable, stylish

/spi'fee/ 1. Said of programs having a pretty, clever, or exceptionally well-designed interface. "Have you seen the spiffy X version of empire yet?" This was common mainstream slang during the 1940s.
2. Said sarcastically of a program that is perceived to have little more than a flashy interface going for it. Which meaning should be drawn depends delicately on tone of voice and context.
[Jargon File]

clean and tidy, groomed, tiddly Grandpa, your car looks real spiffy. Did you polish it?

Synonyms and related words:
OK, ace-high, bad, bandbox, bang-up, bonzer, boss, braw, bully, but good, chic, classy, clothes-conscious, cool, corking, cosmopolitan, crackerjack, dandy, dapper, dashing, delicious, doggy, dressed to advantage, dressed to kill, ducky, elegant, exquisite, fab, fine and dandy, gear, genteel, great, groovy, heavy, hot, hunky-dory, jam-up, jaunty, just dandy, keen, marvy, mean, natty, neat, nifty, nobby, okay, out of sight, peachy, peachy-keen, posh, recherche, ripping, ritzy, rum, sassy, scrumptious, sharp, slap-up, sleek, smart, smashing, smug, snazzy, soigne, soignee, solid, something else, sophisticated, spiffing, spruce, stunning, style-conscious, swank, swanky, swell, tough, tricksy, trig, trim, well-dressed, well-groomed, wizard