This paper explores the concept of nullity of legal affairs with a special focus on defects of will. Historically, Roman law had a significant influence on the development of nullity of legal affairs, which will be analyzed in the second chapter. In the introduction, the paper defines the concept of legal work and explains the conditions of nullity, with special reference to the key conditions. Furthermore, the invalidity of legal transactions is considered and divided into two categories: harmless and pious. Within this topic, conversion and convalidation are also discussed as ways of bridging the invalidity of legal transactions. The consequences of invalidity and its influence on legal relations are analyzed. The main part of the paper focuses on defects of will as the cause of invalidity of legal affairs. Concrete examples of lack of will that lead to destructiveness and examples of lack of will that lead to cowardice will be presented. At the end, he will summarize the key conclusions of the work on the nullity of legal affairs and the importance of recognizing and understanding lack of will in the legal framework. The paper points to the need for thorough analyzes of legal affairs in order to ensure the validity and fairness of legal relationships and provides guidelines for further research and application of this important legal concept.