The article explores the features of adaptation of a foreign component ‘fest’ in modern Ukrainian. It is found that, according to its grammatical nature, borrowing ‘fest’ is a reduction that has come in the modern Ukrainian lexicon from Germanic languages, replacing the usual full form ‘festival’ and retaining its lexical meanings. In modern Ukrainian speech the foreign component ‘fest’ functions as a real masculine noun of the second declination, which is also characterized by the grammatical category of the number, implemented in the singular and plural forms, but it has not been recorded in Ukrainian lexicographic works yet. It is established that in modern Ukrainian the borrowed component ‘fest’ has a high word-building activity and forms new derivatives in morphological ways of word-building, for the most part juxtaposition and rarely drafting of stems. The correspondence of spelling of the new derivatives to the current spelling norms is analyzed, the typical violations of the current Ukrainian spelling rules are revealed and the normative spelling variants of the new juxtaposits are proposed. It is proved that common names of cultural and artistic gatherings, which have the borrowing ‘fest’ in their structure, are unacceptable and understandable not for all Ukrainian native speakers because the formation and spelling of these nominations contradict the norms of modern Ukrainian literary language and have a devastating impact on its traditions. The usual adjective and noun constructions for the nomination of festivals are offered.