Agency or Agenticness is the property of effectively acting with an environment to achieve one's goals. A key property of agents is that the more agentic a being is, the more you can predict its actions from its goals since its actions will be whatever will maximize the chances of achieving its goals. Agency has sometimes been contrasted with sphexishness, the blind execution of cached algorithms without regard for effectiveness.
One might lack agency for internal reasons, e.g., being a rock that has no goals and no ability to act, or for external reasons, e.g., being a child who is granted no freedom to act as they choose.