Synonyms and antonyms.

Synonyms and antonyms.
Synonymy.
Synonyms are the words of the same part of speech different in their sound-form but similar in their meaning and interchangeable at least in one context.
There are very few perfect synonyms. They usually differ in some aspect of their meaning — according to tis they can be ideographic (differ in denotational component: referential and conceptual) and stylistic (connotational component: emotive charge and stylistic reference).
Ideographic synonyms express the same concept but present it in slightly different ways (clever-intelligent-bright).
Stylistic (to love -to adore; insane-mad).
Some stylistic synonyms express dialectic difference (autumn-fall).
The native word is usually more neutral. The borrowed — more official (work-labour — double-scaled pattern; to rise-to mount-to accent — triple-scaled pattern).

Antonymy (semantic opposition).
Antonyms are words which express opposite or contrasting meanings.
Antonyms are subdivided into:
1. Gradable — represent the extremes of the quality. There are often adjectives that can be placed on the scale between them (hot-cold).
2. Contradictory-complimentary — cannot exist without each other (dead-alive; leave-stay)
3. Conversive — describe opposite attributes of the same situation (to buy-to sell — when one buys another sells)