In all above illustrated cases the registered borders are not distinct and the words may get involved into synonymic and antonymic relations.

This class of words may be expanded by jargon, slang, dialect and vulgar words.

A great role belongs to the stylistically coloured words of elevated tone in poetry. They are known as poetic words and in their composition rather heterogeneous. Among them we can find:

- archaisms: affright  alarm, coil  disturbance, commix  to mix, delve  dog, betwixt – between, vale – valley, quoth  said, adawn – dawn;

- historisms: argosy - large merchant ship, cask  helmet,

- lexico-semantic variants of secondary importance: delicate – delightful; depart  to go away

- pure poetic words: anarch, babe, Albion, brine, etc.

1.3. Vulgarisms are coarse words with a strong emotive meaning, mostly derogatory, normally avoided in polite conversation. History of vulgarisms reflects the history of social ethics. So, in Shakespearean times people were much more linguistically frank and disphemistic in their communication than in the age of Enlightenment, or the Victorian era, famous for its prudish and reserved manners. Nowadays words which were labelled vulgar in the eighteenth and nineteenth centuries are considered such no more. In fact, at present we are faced with the reverse of the problem: there are practically no words banned from use by the modern permissive society. Such intensifiers as "bloody", "damned", "cursed", "hell оf” and even ‘shit’, formerly deleted from literature and not allowed in conversation, are not only welcomed in both written and oral speech, but, due to constant repetition, have lost much of their emotive impact and substandard quality. One of the best-known American editors and critics Maxwell Perkins, working with the serialized 1929 magazine edition of Hemingway's novel A. Farewell to Arm found that the publishers deleted close to a dozen words which they considered vulgar for their publication. Preparing the hard­cover edition Perkins allowed half of them back ("son of a bitch”, "whore", "whorehound," etc.). Starting from the late "fifties no publishing house objected to any coarse or obscene expressions. Consequently, in contemporary West European and American prose all words, formerly considered vulgar for public use (including the four-letter words), are even approved by the existing moral and ethical standards of society and censorship.

Each of the above-mentioned groups justifies its label of special colloquial words as each one, due to varying reasons, has application limited to a certain group of people or to certain communicative situations.

1.4. Stylistically neutral units of language.

The words which make a group of stylistically neutral units manifest the following characteristic features:

a) direct relation to a referent;

b) no subjective and evaluative connotations in the meaning structure;

c) rigid borders of reference;

d) no synonymy or simply denotative character of synonymy for the words of terminological character: table - desk; chair - armchair; лингвистика - языкознание.

e) no antonymy as in 1) terminological units: cyclotron, ohm, deep/surface structure, тангенс, котангенс; 2) nomenclature words in systemic naming as: types of aircrafts: штурмовик, перехватчик, бомбардировщик; ‘разведчик’ ‘ракетоносец; warships: aircraft-carrier, destroyer, cruiser, submarine, etc.

Among them there are also: historisms - стрелец, гетман, отрок,an olderman; some lexical neologisms – sputnik, грузовик, ускоритель – accelerator, space-craft, reactor; exotisms - бистро, коррида, corrida, matador, шнапс, пирога, wigwam, etc.

All these words are stylistically-neutral.