The article is devoted to the analysis of a fragment of Kyiv Rus’ linguistic picture of the world and to the reconstruction of human ethic orientations of the Early Middle Age. The aim of this scientific research is to highlight the semantic scope and functions of language units in the Kyiv-Pechersk Patericon are to describe the moral and ethic portrait of a monk. The proposed theme of a study allows updating the analysis aimed at the reconstruction of the Old Ruthenians ethical ideals. The Kyiv-Pechersk Patericon is the first original collection of lives of the Old East Slavic saints of the 13th century. It does not only fully describe the images of the first Rus’ ascetics, but thanks to its unique structure it is the only one among the East Slavic written papers, which gives a valuable possibility to unite different materials into a holistic picture of the moral life in ancient Kyiv. The linguistic means of depicting the moral and ethical characteristics of the inhabitants of the monastery became the subject of the study. It is concluded that in the selection of the characteristics of the monks in the text under consideration there is a tendency to idealize, focus on the literary etiquette norms and highlight the concept of the honor of the clergy. A special attention is paid to such qualities as the allegiance to Christian teaching, humbleness, restraint, mercy, expressed through about 40 positively connotated substantive and adjective lexemes (some negative characteristics are isolated and, therefore, are not involved in the analysis). The selected names don’t perform any terminological functions (they are not components of the titles of the highest ranks of the clergy or namings of the faces of holiness) but rather represent moral and ethical characteristics. In the use of most part of laudatory epithets-definitions there is a tendency to associate them with a specific person, which in the process of further canonization will be the basis for the inclusion of each of them in the certain category of sainthood. According to the origin and character of their use, these lexemes pertain to the church-bookish element. The consistency in refusing to borrow Greek or Latin words to denote the holiness idea indicates a high level of language and cultural-religion consciousness and can be regarded as the main feature of the Slavic choice in denoting this idea. The proposed article considers one of the fragments of the lexical originality of the Kyiv-Pechersk Patericon, which opens us prospects for further studies of this ancient text at different language levels.