The assimilation of synonyms consists in parallel development

E.g. pejorative meanings acquired by the nouns wench, knave and churl which originally meant "girl", "boy", and "laborer" respectively. This loss of old dignity became linguistically possible because there were so many synonymous words of similar meaning. As the result all the three words underwent degradation in their meanings:

wench → indecent girl;

knave → rascal;

churl→ country man.

5) Synonyms connected with non-literary figurative use of words in pictorial language:

e.g. dreamer – star-gazer;

profession – walk of life.

6) Synonyms – euphemisms and vulgarisms employed for certain stylistic purposes:

e.g. to steal – to scoop;

to lie – to distort facts.

7) Some synonymic oppositions appeared due to shift of meaning, new combinations of verbs with postpositives and compound nouns formed from them:

e.g. to choose – to pick up;

arrangement – layout;

to enter – to come in

8) Synonyms developed due to shortening:

e.g. examination – exam; doctor – doc; memorandum – memo.

Antonyms

Antonyms are two or rarely more words of the same language belonging to the same part of speech, identical in style and nearly identical in distribution, associated and used together so that their denotative meanings render contrary or contradictory notions.

Antonymy is not evenly distributed among the categories of parts of speech. Most antonyms are adjectives, which seems to be natural because qualitative characteristics are easily compared and contrasted, e.g. high – low, wide — narrow, strong— weak, old—young, friendly – hostile.

Verbs take second place. E.g. to lose – to find, to live – to die, to open – to close, to weep – to laugh.

Nouns are not rich in antonyms, e.g. friend – enemy, joy – grief, good – evil, heaven – earth, love – hatred.

Antonymic adverbs can be subdivided into two groups:

a) adverbs derived from adjectives: warmly – coldly, merrily – sadly, loudly – softly;

b) adverbs proper: now – then, here – there, ever – never, up – down, in – out.

In the semantic structures of all words, which regularly occur in antonymic pairs, a special antonymic connotation can be singled out.

E.g. the semantic structure of hot can be said to include the antonymic connotation of " not cold", the semantic structure of enemy –the connotation of "not a friend".

A careful examination will reveal three kinds of oppositeness of meaning represented by the following pairs of antonyms. Consider: a) narrow – wide, small – large, tall-short; b) alive – dead, male – female, open – shut; c) over – under, receive – give, wife – husband.