spiff 1
/spif/ , v.t. Informal.
to make spiffy (usually fol. by up ): Let's spiff up this office with new furniture.
[ 1875-80; perh. v. use of dial. spiff well-dressed; see SPIFFY ]
spiff 2
/spif/ , Slang.
n.
1. a bonus or other form of remuneration given to retail salespeople for promoting the products of a particular manufacturer.
v.t.
2. to reward (a salesperson) with a spiff.
[ 1855-60; orig. uncert. ]