Antonyms and synonyms are used for bigger expressiveness of the speech. They are multiple-valued words, and it means that in any given context any one value is updated.
Synonyms designate the same concept, have an identical lexical meaning, but differ on an emotional okrashennost, expressivity, fixedness behind a certain style. Enrichment of language with synonyms goes various ways. First, within effect of laws of individual thinking, secondly, at consolidation of national language, and, thirdly, thanks to development of writing in foreign language. Accumulation of synonyms in language leads to their differentiation. A nest of synonyms - the words entering into one certain group so call - keep differences in the shades. It is the result to their belonging to vocabulary of various population groups, different types of speech communication. Sometimes they completely lose the sinonimichnost. Slavyanizm can be an example of it.
To define various shades of synonyms, it is necessary: to compare everyone with the most abstract concepts; to pick up antonyms; to replace with other synonym; to consider its grammatical structure.
Antonyms are opposed to synonyms and represent the words of one part of speech various on sounding and writing and also the having opposite lexical meanings. Antonyms have quite broad classification: they are divided by type of the expressed concepts; on structure and in terms of language and the speech. The first category is presented by kontradiktorny correlates which mutually supplement each other (lie truth); the contrary correlates expressing polar values (black-gray-white); the vector correlates expressing divergence of actions or signs (revolution counterrevolution); (to lose-find) the konversiva describing the same process from a position of the different points of view. Among antonyms there are no such parts of speech as proper names, pronouns and numerals.