“Societal” as an adjective has been in existence for a couple of centuries, but has become widely used only in the recent past. People who imagine that “social” has too many frivolous connotations of mere partying often resort to it to make their language more serious and impressive. It is best used by social scientists and others in referring to the influence of societies: “societal patterns among the Ibo of eastern Nigeria.” Used in place of “social” in ordinary speech and writing it sounds pretentious.