Expressive expressions of qualitative characterization as non-isosemic constructions coincide in form with existential sentences. Existential construction is used metaphorically: gde est’ chto (existence) → v kom / chem est’ kakoy-to priznak (qualitative characterization), formed by non-isosemic filling of its positions. Thus, the lexeme of locative semantics is replaced by a combination v kom / v chem (in whom/in what), with the possible choice of prepositional-case forms limited to the only form of the prepositional case with the preposition v (in). The subject and predicate positions in isosemic and non-isosemic existential structures are replaced by words of different denotative classes. In the sentences of existence, the subject is expressed by nouns, denoting objects of an external, sensually perceived world. The sentences of qualitative characterization have their subject position occupied by words of qualitative semantics denoting distinctive, permanent qualities, resulting in the semantics of existence drifting towards qualitative characterization. Thus, the verb est’ (to be) as the predicate of existence does not literally express existence but performs a service function. Unlike the isosemic existential constructions, non-isosemic constructions of qualitative characterization lack variation in person and number, with the isosemic verb position being obligatory and the structure having a non-variative form. Non-isosemic expressions have additional semantic components: non-categorical designation of a feature, uncertainty of the author of the statement about the characteristics of the subject, and low trait manifestation degree. With certain restrictions on how the subject and predicate positions are filled, the non-isosemic structure features additional meanings: modus, evaluative, expressive, intensity values, etc.