A more thorough explanation:

The Yick Wo doctrine, also known as the Yik Woh principle, is a legal principle that states that a law or ordinance that gives a person or entity absolute discretion to grant or deny permission to carry on a lawful business violates the 14th Amendment to the U.S. Constitution.

For example, in the case of Yick Wo v. Hopkins, a laundry owner named Yick Wo was denied a permit to operate his laundry business in San Francisco because of a discriminatory law that was selectively enforced against Chinese immigrants. The Supreme Court ruled that the law violated the 14th Amendment because it gave the city officials arbitrary power to discriminate against certain individuals based on their race.

The Yick Wo doctrine is important because it protects individuals and businesses from arbitrary and discriminatory actions by government officials. It ensures that laws and regulations are applied fairly and impartially, without regard to a person's race, ethnicity, or other protected characteristics.