A more thorough explanation:

The rational basis test is a way for courts to determine if a law or ordinance is constitutional. It is one of three judicial review tests.

To pass the rational basis test, the law or ordinance must have a legitimate reason for existing, and there must be a logical connection between the law's goals and the way it is carried out.

The rational basis test is the least strict of the three judicial review tests. It is used when there are no fundamental rights or suspect classifications at issue.

An example of a law that would pass the rational basis test is a law that requires people to wear seat belts while driving. The legitimate reason for this law is to keep people safe in case of an accident. The logical connection between the law's goal and the way it is carried out is that wearing a seat belt can help prevent serious injuries in a car crash.

An example of a law that would not pass the rational basis test is a law that requires people with red hair to pay higher taxes. There is no legitimate reason for this law, and there is no logical connection between the law's goal (raising revenue) and the way it is carried out (discriminating against people with red hair).