The best choice for finding synonyms and antonyms of a word would be a thesaurus.
The best reference source for finding synonyms and antonyms of a word is a thesaurus. A thesaurus is specifically designed to provide alternative words with similar or opposite meanings. To utilize a thesaurus, you can search for the word you are interested in, and it will provide you with a list of synonyms (words with similar meanings) and antonyms (words with opposite meanings).