Intelligence
What is Nation-state actor?
A threat actor working for, or directed by, a government, usually for espionage, sabotage or, in some cases, revenue generation.
A nation-state actor is a group that works for a government or under its direction. Their goals are usually espionage, pre-positioning for sabotage, influence operations or, in a few cases such as North Korea, stealing money for the state.
State actors tend to have more resources, more patience and access to zero-day exploits, but they also make mistakes and reuse infrastructure. Formal attribution to a state is usually made by governments, based on evidence that is only partly public.