Synonyms are words that have the same or nearly the same meaning. Antonyms are words with opposite meanings. There are several types of antonyms including gradable, relational, and complementary antonyms. Hyponyms are words that fall under the same broader category or hypernym. For example, different colors are hyponyms of the hypernym "color" and various musical instruments are hyponyms under the category of "musical instruments". The document discusses the definitions and examples of synonyms, different types of antonyms, and hyponyms.