"Unfair competition" is a term that applies to dishonest or fraudulent rivalry in trade and commerce. It's a branch of intellectual property law that particularly relates to the practice of endeavoring to substitute one’s own goods or products in the market for those of another for the purpose of deceiving the public. But it can take some other forms as well.

.imitating or counterfeiting the name, title, size, color scheme, patterns, shape or distinctive peculiarities of an article. It can also occur by imitating the shape, color, label, wrapper or general appearance of the package in such a way as to mislead the general public or deceive an unwary purchaser."

Acts of unfair competition are generally characterized by deception, bad faith, fraud, or oppression—the competition is such that the victim is thwarted or prevented from successfully engaging in trade.

They're perceived as being against public policy because of their tendency to unduly hinder competition, and this affects the greater good of the public. Unfair competition laws have been established to protect consumers and businesses and to help prevent illegal merchandising.