A more thorough explanation:

Definition: Legitimate means something that is lawful or right. It can also refer to an individual who was born to married parents. When used as a verb, it means to make something legal or proper.

• John's business is legitimate because he follows all the laws and regulations.
• The legitimate heir to the throne is the king's eldest son.
• The government is working to legitimize the use of renewable energy sources.

The first example shows how legitimate is used to describe something that is lawful. John's business is legitimate because he follows all the laws and regulations. The second example shows how legitimate is used to describe an individual who was born to married parents. The legitimate heir to the throne is the king's eldest son. The third example shows how legitimate is used as a verb to mean making something legal or proper. The government is working to legitimize the use of renewable energy sources.

Legitimacy is an old concept from traditional Western common law regarding the status of children when they were born. Illegitimate children, children who were born to unmarried parents, were often referred as bastards or love-children. Today, this concept of legitimacy regarding the status of children has generally fallen out of use.

Legitimacy is also a concept sometimes used in criminal law or other areas of the law. Specifically, in this context, it is sometimes is used to distinguish that an action may be legitimate but not legal, or vice-versa. In simpler reasoning, laws should be obeyed because they are the right thing to do, or rather are legitimate. Following this logic, sometimes the law is not the right thing to do, or rather is illegitimate.