General Online Dictionaries:
* Merriam-Webster: [https://www.merriam-webster.com/](https://www.merriam-webster.com/)
* Oxford Dictionaries: [https://en.oxforddictionaries.com/](https://en.oxforddictionaries.com/)
* Dictionary.com: [https://www.dictionary.com/](https://www.dictionary.com/)
* Vocabulary.com: [https://www.vocabulary.com/](https://www.vocabulary.com/)
* Wordnik: [https://www.wordnik.com/](https://www.wordnik.com/)
These dictionaries often have a feature to look up synonyms and antonyms for specific words.
Specialized Antonym Websites:
* Antonym.com: [https://www.antonym.com/](https://www.antonym.com/) - This site is dedicated specifically to finding antonyms.
* Thesaurus.com: [https://www.thesaurus.com/](https://www.thesaurus.com/) - This site is primarily a thesaurus, but it does include antonyms as well.
Other Resources:
* Google Search: You can simply search for "antonyms of [word]" in Google. This will often bring up results from dictionaries and thesaurus websites.
* Wikipedia: While not specifically focused on antonyms, Wikipedia articles often include information about the opposite of a word.
* Thesaurus Apps: There are various thesaurus apps available for both Android and iOS devices, which can provide antonyms for words.
Remember that the best resource for finding antonyms will depend on your specific needs. If you're looking for a comprehensive list, a general dictionary or a specialized antonym website is a good choice. If you need a quick and easy way to find antonyms, Google Search or a thesaurus app might be more convenient.