The origin of the phrase 'government failure' as a term of art is in critique of government regulation that emerged in the 1960s, which premised that 'market failures' were the only legitimate rationale for regulation. Although the phrase and its relatives (e.g., 'government breakdown,' 'regulatory failure') are frequently used in scholarship and politics, its meaning has been quite ambiguous. Ideological influences and casual uses of the phrase have blurred its understanding, casting doubts over its scope and affecting preferences for regulatory policies. Specifically, this ambiguity has contributed to an artificial distinction between government action and inaction, has elevated the significance of regulatory imperfections, and has contributed to resulted in welfare losses. This essay clarifies the meaning of government failure in regulation and seeks to establish a coherent meaning for the term 'government failure' and its synonyms.