The article discusses the problem of studying the semantics of the word “cowardly” in the Russian language of the 18th and 19th centuries. The meaning of this lexeme has radically changed over time – this is evidenced by contexts from various sources (both documentary, scientific, and artistic). At the beginning of the 18th century, the word “sneaky/cowardly” was fixed in the General Regulations and Regulations of the Chief Magistrate, developed by Peter I; it was used there as a social term denoting certain social classes. Since the 1730s the lexeme “cowardly” is also used in a stylistic sense – now it is a characteristic of the speech features of those “ignoble” social strata that were mentioned in Peter’s Regulations (the speech of the people is cowardly speech). In this sense, the word appears in the works of Lomonosov, Trediakovsky, Kantemir, etc. However, after the publication of Catherine II’s Mandate (1767), which strictly regulated the social structure of society, established clear boundaries of classes and their names, the generalizing concept of “cowardly” turned out to be no longer necessary. But the lexical item itself has not disappeared from the language – it has developed a new meaning. Since the end of the 18th century “cowardly” is a moral characteristic of a person, as well as of an unworthy act, an ignoble manner of behavior (this, apparently, was typical, first of all, for the representatives of those “ignoble” social classes). This new semantic meaning of “cowardly” gradually took root in the language and displaced the previous meaning. In the Dictionary of the Russian Academy (1789–1794) the first meaning recorded is still the social meaning of the word “cowardly”, the second – a new, moral one. In the Dictionary of Church Slavonic and Russian (1847), the priority of meanings has been changed: now the moral and ethical semantics of the word is given as the main one. In the lexicographical works of the twentieth century, “cowardly/sneaky” in the meaning of the social term is even marked as obsolete. The theoretical provisions in the article are substantiated by examples of this word’s functioning in dif- ferent periods in different meanings.