Wars of national liberation are conflicts fought by people who want to gain independence or freedom from a government that they don't like or don't agree with. It's like when you don't want your parents to tell you what to do anymore, so you try to become your own boss.
Let's say you live in a country that is controlled by another country or a ruler who doesn't treat you and your people fairly. You and your friends and even your family might want to fight against that ruler to try to get your own independence or freedom.
These kinds of wars are often long and difficult because the government or ruler you're fighting against has more weapons, money, and resources, and might have a bigger army or police force. But sometimes, if enough people are willing to fight for their cause and they have support from other countries or groups, they can eventually win.
Many countries have fought wars of national liberation throughout history, including the United States, India, South Africa, and Vietnam. These wars can be very important in helping people gain their freedom and control their own lives.