The problem of indeclinability in the Russian language, remained for linguistics not new by the beginning of the 21st century, it went beyond the framework of the traditional morphological description.  There are about 2 000 indeclinable names with objective meaning in Russian today. More than 90 words are multi-valued among them, including many color markings. Extensive series of non-inducible anthroponyms, toponyms and abbreviations have formed. An analysis of the grammatical reduction of non-declining names cannot be isolated. Performing a nominative function they as lexical units are distributed according to the “ideographic” [3] principle into 18 thematic groups [4]. This principle of systematization “… allows us to fully and comprehensively establish a connection between words and designated phenomena; find out the volume of meanings of words, their use; to determine the specific weight of these groups in the vocabulary of the language, their growth or reduction, depending on external historical circumstances; to establish to some extent stylistic differentiation within a thematic group” [3: 122]. The largest in the number of words and the most open at the same time is the thematic group of “faces” — 89 words, and the smallest and most closed is the group “name of the winds”.

Russian linguists paid attention to this grammatical phenomenon mainly within the boundaries of the formal typological approach. Most of the research are made in the 70-90s of the twentieth century: in them, indeclinable names are qualified either in full accordance with the term “indeclinable noun”, as words with one wordform, or as inclined, but with complete grammatical homonymy of all numerical and case word forms.

Unchangeable names attract the attention of many researchers in the framework of an active discussion about the growing role of analyticity in the Russian language at the turn of the twentieth and twenty-first centuries (the works of E.A.Bryzgunova, N.S.Valgina, M. Ya.Golovinskaya, E.A. Zemskaya and also the works of A.A.Kolesnikov, I.A. Melchuk, N.V. Solntseva, T.V.Tukova). If we generalize some studies on the  languagestypology  ​​(A.E.Kibrik, E.V.Klobukova, Yu.P. Knyazev, V.A.Plungyan, B.A.Uspensky) [1: 10-27], the facts of coexistence in Russian language ofchangable and unchangeable forms of names [coat, domino, beige, Bordeaux] and verbs [skok, bats] can be explained simply: Russian has a high degree of grammaticality. This casts doubt on the movement of the Russian language towards analyticism. Most likely one should recognize the politopologism of the Russian language (L.G.Zubkova), since it has a rich arsenal of formal means of expressing grammatical categories and combines different grammatical tendencies (fusion and agglutination, synthetism and analyticism) [5].

Scientific notions of nouns with formal reductions are reflected in the synonymy of terms: “syntactic nouns” (A.M. Peshkovsky, V.N.  Nemchenko), “morphologically defective” (L.V.Knorin), “morphologically bared” (M.V. Panov), “unchangeable words that are beyond declination” (V.V.Babaytseva),  “analytical” (N.P.Kolesnikov), “non-grammatical” or “indexed” (O.S.Akhmanova), etc. In order to neutralize the competition of the terms “indeclinable” and “immutable” nouns, we use the term “deklinatsionny” names. The joining of the prefix de is used its meaning “loss of something” to the Russian verb “to tilt” (from the Greek klino) is interpreted by us against the background of general dialectical processes in the development of language as “deviation from declension”. The term “indeklinatsionny”  (O.S. Akhmanova) is the equivalent of the name of non-inducing parts of speech which is better, in our opinion, used to determine the syntactic function of such words: in Russian priekhalinkognito, zabezhal v kafe, pel solo (in English translation: he arrived incognito, ran into a cafe, sang solo).

The term constellation is convenient for denoting indirect categorization by the principle of “free dependence”. This principle was analyzed by L. Yelmslev in his work “Prolegomena to the Theory of Language” (1943), where he examines the interconnection of the language system and its structure which is an autonomous entity with internal dependencies. These dependencies are manifested between the interrelated elements in such a way that each element becomes what it really is only through relationships with other elements [1: 11]. We took into account the fact that indeclinable names stand outside the system of Russian inflection, they possess a hieroglyphic character, but it does not contradict the grammatical system of the Russian language in which there are unchangeable words (adverbs, service parts of speech). Therefore, their grammatical categories are not manifested paradigmatically; not through word modification, but syntagmatically; through linear relations with other linguistic units. Formally, they are free from inflectional inflexion, but are dependent on neighboring units with their grammatical meanings [4].

The indeclinability of names is often considered as an asystem phenomenon of Russian grammar, but if it does not destroy the systemic structure of the language then it should be recognized as a derivative of the system. Such fact increases the vulnerability in the recognition of analyticity, because  there is no clear correlation between the grammatical and lexical meanings  in Russian that is characteristic of pure analyticity and the morphological categories of the declination name are expressed in one of the substituting members. Indeclinable names such as [taksi, zhalyuzi, kashpo, domino] (in Russian: такси, жалюзи, кашпо, домино) not accidentally often correspond in shape to root morphemes, which do not have a formal expression of the paradigm. However, if inflexion appears, they become agramatic. Agrammatism (everyday, creative) of indeclinable names [2], i.e. their use in the wrong morphological form [mnogopol’t, ekhat’  nametre, v bigudyakh, u zhalyuzey] (in Russian: много польт, ехать на метре, в бигудях, у жалюзей)  should be regarded as a phenomenon of dynamic morphology, which objectively reflects the trends of language transformations.

Declinable (deklinatsionnye) nouns have a property similar to the hieroglyphs, out of context they transmit the non-actualized concept of the subject. They receive their morphological properties in the context, linearly, i.e. syntagmatic ally where one of the coordinated words performs the function of a grammatical regulator. Therefore, indeclinable names  are implicitly provided with a full set of grammatical categories on the principle of “free dependence” -constellationwithout own word-change which does not contradict the possibilities of the grammatical system of the Russian language. The terms we offer expand the traditional notion of non-declinability phenomenon  taking into account the diversity of approaches in its study at the present stage.