The word-formation specificity of diminutive vocabulary in Russian and Arabic is considered in this paper. On the background of the fact that the definitions of diminutives in various linguistic traditions do not always reveal the morphological features of this lexical layer, the authors focus on the word-formation motivation in creating diminutives in Russian and Arabic, which becomes the subject of the study. In this regard, special attention is paid to the criterion of O.G. Vinokur and his Arabic parallels are the parameters of the Arabic medieval philologist Ibn Faris, which serve as the basis for revealing the structure and semantics of derivative words in both languages. The authors, resorting to the comparative method, analyze the range of meanings and connotations resulting from the word-formation motivation of diminutive vocabulary in both languages - diminutiveness, endearment, reduction of quantity, including the closeness of time and place specific to the Arabic meaning and amplification of meanings and their expression in both languages. The basics of translating diminutive vocabulary are also not overlooked. Highlighting three important foundations of translation adequacy - structural, semantic and cognitive, which affect the translation process when equivalence is achieved, the authors come to the conclusion about the complexity of the relationship and, accordingly, the translation of diminutives. To do this, the authors in their reasoning leave the sphere of pure linguistics and turn to the culturological sphere, without which today it is unthinkable to talk about a full-fledged translation activity. The work contributes to theoretical linguistics as a comparative study of the Semitic and Slavic languages, and also complements the missing link in the relatively young private theory of Russian-Arabic translation.