EN
In this paper, the author analyses the Polish nouns czyn (an act) and wyczyn (a feat). She aims to fi nd semantic differences between these units. The author quotes selected dictionary defi nitions, analyses examples from NKJP (National Corpus of Polish); in her discussions, she refers to both philosophical theories (by H. Arendt, Cz.S. Bartnik, R. Ingarden, K. Wojtyła), and linguistic diagnoses (by A. Bogusławski, M. Danielewiczowa, I. Duraj-Nowosielska, A. Wierzbicka). The author concludes that, despite the guidance provided in some lexicographic studies, the lexeme wyczyn cannot be defi ned with the phrase ‘wyjątkowy czyn’ (an exceptional act).