The article analyses the formation of the term infinitive in the Ukrainian language. It is emphasised that the development of the Ukrainian written and literary language and the expansion of its functional spheres occurred in the 16th and 17th centuries. It was during this period that the grammatical system, in particular the verb as a complex multi-level category, attracted the attention of scholars such as Lavrentii Zyzanii, Meletii Smotrytskyi, and others. The group of scientific terminology of the Institute of Ukrainian Language of the National Academy of Sciences of Ukraine is currently working in the historical and terminological direction, processing sources for the compilation of the ‘Historical dictionary of linguistic terminology’. The proposed article has the same focus ‒ to analyse the term infinitive in the Ukrainian language in its diachronic and synchronic dimension. In terms of its functional capabilities, it is basic both for the verb part of speech and grammar in general. The origin of the term from the Late Latin infinitivus and its equivalents in Western Europe-an languages is clarified. The genesis of the term is traced back to the earliest grammars (Smotrytskyi, Pavlovskyi). The results of the study of scientific sources of the 16th ‒ 20th centuries are systematised depending on the functioning of the term infinitive in them. The diachronic lexical, semantic and accentual variants of the term are described, and it is compared with the corresponding modern terms. Particular attention is paid to the fact that, given the verb-noun nature of the infinitive, the problem of its status in the system of parts of speech is interpreted rather ambiguously in scientific sources. In the Ukrainian morphological terminology, the term indefinite form of the verb is used in parallel with the above, according to the sources we have identified. The syntactic role of the infinitive is traced, in particular, the function of the main and secondary members of the sentence. The emphasis is placed on the remarks made by K.H. Horodenska at the presentation of the publication ‘Language Commentary to the Constitution of Ukraine and Other Regulatory Acts’ (April, 2025): ‘The use of verbal nouns in scientific, official and business styles of speech requires their replacement with infinitives’. It is emphasised that the genesis of the terms infinitive and indefinite verb form as the initial form of the verb has its own special significance related to their correct and appropriate use in different styles of the modern Ukrainian language.
Ninа Yatsenkо (Wed,) studied this question.