The phrase "be in keeping" can be understood as something that is consistent with a certain theme or standard. The antonym for this phrase would be "out of keeping", which denotes something that is not in alignment with the expected theme or standard. It is an antonym that can be used to convey a deviation from the norm or a lack of consistency. Other antonyms for "be in keeping" might include words such as divergent, contrary, or discordant. These words are additional descriptors that suggest a lack of agreement or cohesion with the theme or standard. Overall, antonyms for "be in keeping" serve to highlight when something does not fit the expected mold or is out of sync with the norm.