Insubordination is the act of willfully disobeying an authority. Refusing to perform an action that is unethical or illegal is not insubordination; neither is refusing to perform an action that is not within the scope of authority of the person issuing the order.

Insubordination is typically a punishable offense in hierarchical organization

Hierarchical organization

A hierarchical organization is an organizational structure where every entity in the organization, except one, is subordinate to a single other entity. This arrangement is a form of a hierarchy. In an organization, the hierarchy usually consists of a singular/group of power at the top with...

s which depend on people lower in the chain of command doing as they are told.
Insubordination is refusal by a subordinate to obey lawful orders given by a commissioned officer or non commissioned officer (NCO).