Definition - What does Substantive Law mean?
Substantive law is the area of law that deals with the rights of citizens and groups. Many different types of law, such as torts, property law, criminal law, wills and trusts law, etc. all have substantive law as a part of their foundation.
Substantive law is an alternative to procedural law. Procedural is the law of how rights are enforced as opposed to identifying which rights individuals and groups have.
Justipedia explains Substantive Law
Essentially, substantive law lets citizens within a given jurisdiction understand which rights are afforded to them by law. Substantive law also defines crimes and punishments.
If a citizen does something that they do not have a right to do under substantive law, they can then face criminal charges. For example, if a person steals something from their neighbor, then they could face criminal prosecution. This would be because the person does not have a right to steal from another person.