A more thorough explanation:

Definition: The doctrine of vested rights is a legal principle that protects the rights of individuals or entities that have acquired a legal right or interest in a property or contract. This means that once a right has been acquired, it cannot be taken away by a subsequent law or regulation.

For example, if a property owner has obtained a building permit from the local government and has started construction, the doctrine of vested rights would protect their right to complete the construction even if the local government changes the zoning laws or building codes.

Another example would be an employee who has earned a pension after working for a company for many years. The doctrine of vested rights would protect their right to receive the pension even if the company goes bankrupt or changes its pension plan.

These examples illustrate how the doctrine of vested rights provides legal protection for individuals or entities who have acquired a legal right or interest in a property or contract. It ensures that their rights cannot be taken away arbitrarily by subsequent laws or regulations.