SYNONYMY

1. General characeristics of synonymy

A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greeksyn (σύν) ("with") and onoma (ὄνομα) ("name"). 

ANTONYMY

1. General characteristics of Antonymy

Antonymy is exemplified by such pairs as long-short, fast –slow, easy-difficult, good-bad, hot-cold.

Antonyms have the following characteristics:

(1) They are fully gradable (most are adjectives, a few are verbs).

(2) Members of a pair denote degrees of some variable property such as length, speed, weight, accuracy, etc.

SEMANTIC CHANGES

1. Semantic changes