Civil Liberties are laws that every* individual has and which cannot be taken away by other individuals or institutions, including the government. Civil Liberties are specified in a legal text(s), such as the Constitution and its amendments (this is the case in the United States and in many other countries) or in treaties, such as the European Convention on Human Rights. Civil Liberties are different from Privileges, and an example for a Civil Liberty is Freedom of speech while an example of a Privilege is the right to draft a will.
* Depending on the context and the country, Civil Liberties can hold for all people or only for the citizens of a given country