spiff [spif ]
verb:
(informal) spruce; make attractive, stylish, or up-to-date - usually used with up
Examples:
The 15-mile Gwynns Falls Trail beckons hikers and bikers; the garden club works to spiff up the landscape. (Mike Klingman,
'Small-town feel, but with big-city amenities': Baltimore’s tiny Dickeyville is quaint and quiet, Baltimore Sun, March 2021)
High-school students used to spiff up their college applications with extracurriculars like Model U.N. and student council. (Ian Chadwick,
Is Every Ambitious Teen-ager a 'Founder and C.E.O.'?, The New Yorker, January 2021)
"The interviewer should be here any moment." Ruth plucked a ball of lint off Kenny's shirtsleeve. "Why not you go spiff up while we wait?" (Hope Callaghan, Key to Savannah)
Origin:
'make neat or spruce,' 1877 (with up or out), probably from spiffy (1853, of uncertain origin). Spiffing 'excellent' was very popular in 1870s slang. (Online Etymology Dictionary)