The problem of definition of synonyms

Synonyms are usually defined as words belonging to one part of speech, close in meaning and interchangeable at least in some contexts. Synonyms are characterized by either the semantic relations of equivalence or by the semantic relations of proximity. As the degree of semantic proximity may be different, different types of synonyms can be singled out. Full (total) synonyms, i.e. words characterized by semantic equivalence, are extremely rare.
The degree of semantic proximity is best of all estimated in terms of the aspects of meaning, i.e. the denotational, the connotational, and the pragmatic aspect.
The highest degree of proximity is observed in synonyms which have similar denotational aspects but differ either in the connotational (1) or the pragmatic (2) aspect of meaning.
• The difference in connotation may be illustrated by the words famous meaning known widely, having fame’ and the word notorious which is defined as ‘widely known because of smth. bad. for example for being criminal, violent, immoral*. Thus, the word famous implies a positive emotive evaluation, and the word notorious — negative.
• The difference in the pragmatic value of words is found in a far greater number of words than the difference in the connotational aspect. It can be observed in synonymic pairs consisting of a native and a borrowed word. In most cases the native word is more informal, whereas the foreign word has a learned or abstract air, cf: brotherly — fraternal.
bodily — corporal. In a few eases these synonymic values are reversed, e.g. deed — action, foe — enemy.
Taking into account the difference of synonyms by the three aspects of their meaning they may be classified into stylistic(different in connotational aspect, children-infants,dad-father), ideographic(diff in denotational aspect,apartment-flat,forest-wood) and ideographic-stylistic synonyms(hardly interchangeable in the context, expect-anticipate).