The article examines the semantic structure of simple adjectives with the suffix -at- (-ат-) in their relationship with single-root composites visible, —vidnij, -obraznij, podobnij (-видный, -образный, подобный) developing the meaning of similarity. The card file of linguistic facts was compiled on the basis of the «Reverse Dictionary of the Russian Language», «The Dictionary of the Russian Language» in 4 volumes and the internet resources. Mono- and polysemic adjectives were selected with the suffix —at— (-ат-), which is combined with 28 bases. Derivation paradigms are formed, which include adjectives with the suffix -at- (-ат-) and single-root composites with suffixes of -vidnij, -obraznij, podobnij (-видный, -образный, подобный), integrable by one or another basis. Derivatives with the suffix —at— (-ат-) comprise seven fourmembered paradigms with composites. Based on internet resources, in each derivational paradigm, compatible series of adjectives were formed, in which the number of adjective actors varies. The maximum number of lexical distributors was recorded in a paradigm with the basics of tarelk— (тарелк-) and shishk— (шишк-). Name distributors are included in various thematic groups. The compatibility analysis of single-root lexical units is intended to reveal certain semantic nuances in the transmission of the attribute of an object and answer the question of whether adjective composites with a similarity value are doublets. Thus, the leading study is the valency analysis.