In a constantly changing world, in a system of positive law subject to systematic changes in tax legislation, where licit tax behaviors can be transformed overnight into illicit tax behavior, through the intervention of the legislator who seeks to include as many behaviors as possible within the scope of tax law in order to supplement budget revenues, the conceptual clarification of the possible legal classifications of certain types of atypical behaviors becomes crucial. This is due to the fact that, despite their use within a shared legal-fiscal register, tax fraud, tax evasion, abuse of rights in the field of taxation, and tax optimization cannot be equated. The substantiation of the regulation of illicit behaviors and the categorical classification of concepts is essential in circumstances where, in law, shades of gray can determine whether legal liability leans toward white (acquittal), or black (conviction). Our approach is syncretic, aiming at the practical application of the frameworks and classifications proposed at a theoretical level. We pursue a dual utility of the study, both from a theoretical perspective, where it may serve as a benchmark for the substantiation of new regulations in this field, and, above all, from a practical perspective, in order to distinguish in concreto between the different types of illicit behavior that have been artificially grouped under the same umbrella of “tax evasion”.