The antonyms for the phrase "acts in response" are many, and they range from simple negations of the phrase to more complex concepts. One antonym could be "acts in opposition," which suggests a deliberate and opposing action to what is being responded to. Another could be "acts in anticipation," which suggests preparing for an event rather than reacting to it. Some others could be "acts in isolation," which would suggest a lack of response, or "acts in ignorance," which suggests unawareness of what is being responded to. Ultimately, the antonyms for "acts in response" are diverse, reflecting the many ways in which people can face a situation.