As Catherine Keener is a proper noun and a person's name, there are no specific antonyms for it. However, the word "antonym" means a word that is opposite in meaning to another word. So, we can explore the antonyms of some adjectives that could describe Catherine Keener. For instance, if we describe her as friendly, we can say that her antonyms are unfriendly, hostile, or mean. If we describe her as beautiful, the antonyms could be ugly, unattractive, or plain. If we describe her as successful, the antonyms could be unsuccessful, failed, or defeated. In conclusion, antonyms cannot be used for a person's name, but we can find them for the adjectives used to describe that individual.