The author shows the rang of the phenomenon, which is semantic difference of lexical derivatives, i.e. the affixal derivatives and the composites. This phenomenon is interpreted in the light of the theory of non-compositionality (“minimal specification view” by R. Dirven). The author described the types of syntactic compression, on which is based the derivation of relative adjectives in the Russian language, taking into account also other European languages. The final part of the article is devoted to the status of relative adjectives in the functional-grammatical system of the language categories.