Wiktionary
n. (alternative spelling of horsetrading English)
WordNet
n. the swapping of horses (accompanied by much bargaining) [syn: horse trade]
negotiation accompanied by mutual concessions and shrewd bargaining
Wikipedia
Horse trading, in its literal sense, refers to the buying and selling of horses, also called "horse dealing". Due to the difficulties in evaluating the merits of a horse offered for sale, the sale of horses offered great opportunities for dishonesty, leading to use of the term horse trading (or horsetrading) to refer to complex bargaining or other transactions, such as political vote trading. It was expected that horse sellers would capitalize on these opportunities and so those who dealt in horses gained a reputation for underhanded business practices.