EN
This paper is dedicated to lexical issues and focuses on describing the phenomenon of the life of words over more than two centuries (from the beginning of the 19th c. to the fi rst decade of the 21st c.). The object of the research is the corpus of texts constituting Rozprawy literackie (Literary treatises) by M. Mochnacki. The aim of the research is to identify and discuss forgotten words, that is such lexical units or their individual meanings as have become obsolete or have gone out of use completely. The analysis falls into the stream of structuralist research and has been performed with the application of the diachronic method.