Branches of linguistics. Synchronic vs diachronic approaches to the language study. Lexicology – ‘the science of the word’

Contradictory antonyms (complementary antonyms) are mutually opposed (exclusive) and deny one another, e.g. male – female; married – single; asleep – awake; same – different. Their features:
-not gradable;
-truly represent oppositeness of meaning;
-cannot be used in the comparative or superlative degree;
-the denial of one member of such antonymic opposition always implies the assertion of the other, e.g. not dead – alive.
Conversive antonyms (conversives) are words which denote one and the same situation as viewed from different points of view, with a reversal of the order of participants and their roles, e.g. husband – wife; teacher – pupil; to buy – to sell; to lend – to borrow; to precede – to follow. These antonyms are mutually dependent on each other and one item presupposes the other.
Vectorial antonyms (directional antonyms) are words denoting differently directed actions, features, e.g. to rise – to fall; to arrive – to depart; to marry – to divorce; to learn – to forget; to appear – to disappear.
Morphological classification of antonyms by V. N. Komissarov (Dictionary of English Antonyms):
root antonyms (absolute antonyms) are antonyms having different roots, e.g. clean – dirty; late – early; day – night;
derivational antonyms are antonyms having the same root but different affixes, e.g. to fasten – to unfasten; flexible – inflexible; useful – useless.
32. Grammatical and lexical valency. Grammatical and lexical context.
The appearance of words in a certain syntagmatic succession with particular logical, semantic, morphological and syntactic relations is called collocability or valency.
Valency is viewed as an aptness or potential of a word to have relations with other words in language. Valency can be grammatical and lexical.