1 Any behavior, conduct, or series of acts by a person. 2A civil or criminal judicial proceeding intended to resolve a legal dispute, claim, or accusation. civil action. An action brought to enforce, protect, or redress a civil or private right or to compel a civil remedy; any action brought other than a criminal action. class action. 1 An action brought by a person or a group of people as representatives of a larger group action in personam who have a common legal claim but are so numerous t...