Urban Exploration (URBEX) is a relatively modern leisure activity that is directly related to the exploration of abandoned and unused buildings, sites and other results of human activity. Urbex is often presented as the exploration of modern ruins and is characterized by a set of unwritten rules to be followed by the so-called explorers (urbexers), which defines urbex as such. Urbex is a phenomenon on the border of the law, but it is not comprehensively scientifically elaborated, especially in the field of typology and defining what urbex is and what it is not. Therefore, the aim of this paper is to elaborate the theoretical concept of urbex within the limits of scientific work, including the determination of its forms and manifestations, and within these, to establish key parameters for identifying the differences between authentic urbex and pseudo-urbex, which in the true sense of the word is not urbex as such. Defining the intermediate form between urbex in the true sense of the word and the absence of urbex is essential for further research, as it allows specifying the subject under investigation. The specification of pseudourbex is an autistic innovation and neologism and is based on a factual confrontation and synthesis of the rules of urbex and its types and forms, which is combined with the author's own knowledge. The topic of pseudourbex itself is not contentious, but is open to further scientific discussion.