Non-state actors are individuals or organizations that are not formally affiliated with or recognized by a state or government. In the context of International Relations, non-state actors can include transnational corporations, non-governmental organizations (NGOs), international organizations, religious groups, and terrorist organizations, among others. Non-state actors can play a significant role in shaping international events and influencing state behavior, and are increasingly seen as important actors in the global arena.
Source: Rosenau, J. N. (1997). Along the domestic-foreign frontier: exploring governance in a turbulent world. Cambridge University Press.