spiffing
adjective
[ ˈspɪfɪŋ ]
• excellent; splendid.
• "it's a frightfully spiffing idea"
Origin:
late 19th century: of unknown origin.
spiff
verb
• make someone or something attractive, smart, or stylish.
• "he arrived all spiffed up in a dinner jacket"
Origin:
late 19th century: perhaps from dialect spiff ‘well dressed’.