Public textual cyberbullying has become one of the most prevalent issues associated with\nonline safety of young people, particularly on social networks. To address this issue, we\nargue that the boundaries of what constitutes public textual cyberbullying needs to be first\nidentified and a corresponding linguistically motivated definition needs to be advanced.\nThus, we propose a definition of public textual cyberbullying that contains three necessary\nand sufficient elements: the personal marker, the dysphemistic element and the\ncyberbullying link between the previous two elements. Subsequently, we argue that one of\nthe cornerstones in the overall process of mitigating the effects of cyberbullying is the\ndesign of a cyberbullying lexical database that specifies what linguistic and cyberbullying\nspecific information is relevant to the detection process. In this vein, we propose a novel\ncyberbullying lexical database based on the definition of public textual cyberbullying. The\noverall architecture of our cyberbullying lexical database is determined semantically, and, in\norder to facilitate cyberbullying detection, the lexical entry encapsulates two new semantic\ndimensions that are derived from our definition: cyberbullying function and cyberbullying\nreferential domain. In addition, the lexical entry encapsulates other semantic and syntactic \ninformation, such as sense and syntactic category, information that, not only aids the\nprocess of detection, but also allows us to expand the cyberbullying database using\nWordNet (Miller, 1993).