What is the meaning of Spiff?

Neat, smartly dressed, attractive.

Attractiveness or charm in dress, appearance, or manner.

A well-dressed man; a swell.

A bonus or other remuneration, given for reaching a sales goal or promoting the goods of a particular manufacturer. Originally from textile retailing, a percentage given for selling off surplus or out-of-fashion stock, of which the sales person could offer part as a discount to a customer.

Alternative form of spliff (hand-rolled marijuana cigarette)

(usually with up or out) To make spiffy (attractive, polished, or up-to-date)

To reward (a salesperson) with a spiff or bonus.

To attach a spiff or bonus to the selling of (a product)

Source: wiktionary.org