A vagueza semântica do termo “legítimo interesse” na legislação brasileira: uma análise linguística

Abstract

The research analyzes the semantic vagueness of the term "legitimate interest" in Brazilian legislation, such as the General Data Protection Law (LGPD), the Code of Civil Procedure (CPC), and the Child and Adolescent Statute (ECA). The central objective is to investigate how the conceptual imprecision of this term impacts legal certainty, the uniformity of judicial decisions, and the effectiveness of fundamental rights protection. The methodology combines linguistic analysis, a theoretical review of relevant authors, and reflection on three real cases with divergent judicial interpretations. The results demonstrate that the absence of objective criteria to define "legitimate interest" generates subjective interpretations, jurisprudential inconsistencies, and risks of abuse, particularly in contexts of power imbalance. For instance, in the LGPD, vagueness allows economic interests to override data subjects' rights; in the CPC, it affects procedural legitimacy; and in the ECA, it compromises decisions regarding minors' well-being. The study concludes that while the term's flexibility is useful for adapting to concrete cases, it requires control mechanisms to prevent a disconnect between legislative intent and practical application. Mitigation proposals include the creation of legislative glossaries with precise definitions, the inclusion of illustrative examples in laws, standardized interpretative guidelines by competent bodies, and continuous training for legal professionals. These measures aim to balance normative adaptability with predictability, strengthening the coherence of the legal system.