Libertarianism is a collection of political philosophies that uphold liberty.
Political philosophy, or political theory, is the study of topics such as politics, liberty, justice, property, rights, law, and the enforcement of a legal code by authority: what they are, why they are needed, what, if anything, makes a government legitimate, what rights and freedoms it should protect and why, what form it should take and why, what the law is, and what duties citizens owe to a legitimate government, if any, and when it may be legitimately overthrown, if ever.
Liberty, in philosophy, involves free will as contrasted with determinism.
Penn Jillette: Why I Am A Libertarian by Libertarianism.org
Libertarians seek to maximize autonomy and freedom of choice, emphasizing political freedom, voluntary association, and the primacy of individual judgment.
Freedom of choice describes an individual's opportunity and autonomy to perform an action selected from at least two available options, unconstrained by external parties.
A voluntary group or union is a group of individuals who enter into an agreement, usually as volunteers, to form a body to accomplish a purpose.
Political freedom is a central concept in history and political thought and one of the most important features of democratic societies.
What Is Libertarianism? by Seeker Daily
Libertarians generally share a skepticism of authority; however, they diverge on the scope of their opposition to existing political and economic systems.
The word authority can be used to mean the right to exercise power given by the State, or by academic knowledge of an area.
Various schools of libertarian thought offer a range of views regarding the legitimate functions of state and private power, often calling to restrict or to dissolve coercive social institutions.
Some libertarians advocate laissez-faire capitalism and strong private property rights, such as in land, infrastructure, and natural resources.
Laissez-faire is an economic system in which transactions between private parties are free from government interference such as regulations, privileges, tariffs, and subsidies.
In the abstract, property is that which belongs to or with something, whether as an attribute or as a component of said thing.
Capitalism is an economic system based on private ownership of the means of production and their operation for profit.
Others, notably libertarian socialists, seek to abolish capitalism and private ownership of the means of production in favor of their common or cooperative ownership and management.
Socialism is a range of economic and social systems characterised by social ownership and democratic control of the means of production; as well as the political ideologies, theories, and movements that aim at their establishment.
In economics and sociology, the means of production are physical, non-human inputs used for the production of economic value, such as facilities, machinery, tools, infrastructural capital and natural capital.
An additional line of division is between minarchists and anarchists.
Minarchism is a libertarian political philosophy which advocates for a particular variety of minimal state that acts only to enforce a universal framework of natural and legal rights essential to the functioning of a free marketplace in economy and culture, and operating through a limited government societally managed according to democratic or republican principles.
While minarchists think that a minimal centralized government is necessary, anarchists propose to completely eliminate the state.