What is Autarky?

Legal Definition
Autarky is the quality of being self-sufficient. Usually the term is applied to political states or their economic systems. Autarky exists whenever an entity can survive or continue its activities without external assistance or international trade. If a self-sufficient economy also refuses all trade with the outside world then it is called a closed economy.

Autarky is not necessarily an economic phenomenon; for example, a military autarky would be a state that could defend itself without help from another country, or could manufacture all of its weapons without any imports from the outside world.

Autarky can be said to be the policy of a state or other entity when it seeks to be self-sufficient as a whole, but also can be limited to a narrow field such as possession of a key raw material. For example, many countries have a policy of autarky with respect to foodstuffs and water for national security reasons.
-- Wikipedia
Legal Definition
An economic system without any external trade, or one where trade is reduced or eliminated through barriers and quotas.