The article discusses legal terminology in the respect of legal studies and linguistics. The paper focuses on the essential consideration of the word used as a legal term from the point of view of its lexical and syntactic relations and lexical meaning. The relevance of the study is due to the need for a clear distinction between related concepts that are key concepts in law: "accused", "defendant", "convicted", "acquitted". The characteristics of these terms is given in accordance with the classification, which is based on a multifaceted approach. An attempt is made to correlate these terms with the words-denominations used in the informal speech of lawyers. The authors conclude that the unprofessional use of established terms and their definitions in real situations of criminal proceedings of the indictment process may entail offense to honor and dignity of a person, violation of their rights as a citizen, as well as question the principle of presumption of innocence. In addition, according to the authors, the process of further humanization of criminal legislation is hampered by the lack of new procedural concepts and terms.