The article focuses on the features of the formation of the lexis of positive moral-ethical evaluation in the Spanish language of the 13–15th centuries. The research is based on the material of the Mediaeval Spanish adjective virtuoso (virtuous), which in the studied period belonged to the core lexis of positive moral-ethical evaluation. This is explained by the role the Church played in the life of the mediaeval society, in the formation of ethical norms and a particular system of values.