Comparative social science concepts such as “illiberalism” and “authoritarianism” are increasingly common terms of art used in academic and policy debates, yet usage patterns and their substantive meaning vary widely across publications and authors. This article presents parsimonious “best-use” conceptualizations of both constructs, underlining the limitations of current, often widely disparate practices. In doing so, it outlines the reasons why this state of affairs is analytically unnecessary, leading to both conceptual stretching and terminological confusion. Illiberalism can most fruitfully be conceptualized positively and ideationally, capturing a distinct form of ideological reaction against hegemonic liberalism, experienced largely over the last several decades, with a variety of case-specific elements. This definition sits in partial contradistinction with other, sometimes-associated concepts such as anti-liberalism, populism, or conservatism and is not associated with regime-type definitionally. Authoritarianism, meanwhile, is most parsimoniously treated as a residual categorization of political regime vis-a-vis the concept of electoral democracy, which accords with the goals for which most scholars deploy it.