The document discusses several types of semantic relationships between words:
1. Synonymy refers to words with closely related meanings that can often substitute for each other, like "answer" and "reply".
2. Antonymy describes words with opposite meanings, like "hot" and "cold".
3. Hyponymy involves a hierarchical relationship where one word includes the meaning of another, like "dog" and "animal".
4. Homophones and homonyms refer to words with the same pronunciation but different meanings or spellings.
5. Polysemy is when one word has multiple related meanings.
6. Metonymy uses one concept to refer to another closely associated concept.