The primary goal of this article is to analyse the use of the term ‘tax avoidance’ in the legislative framework and case law of the European Union to point out the absence of a common linguistic approach. The consequences derived from the terminological chaos will also be discussed; thus, the study will try to display how big and deep the problem is by giving special attention to the semantic aspects that cannot, in fact, be ignored anymore. Furthermore, the principles stemming from the case law will be reviewed, since they are regarded as the outcome of the interpretation of tax avoidance by the judiciary.