"Acted with regard to" implies a certain level of thoughtfulness and conscientiousness in one's actions. Antonyms for this phrase might include "acted recklessly," "acted without consideration," or "acted negligently." These terms suggest that the individual did not take the time to fully understand the consequences of their actions or failed to consider the impact on others. Additionally, antonyms for "acted with regard to" might include "acted selfishly," "acted impulsively," or "acted thoughtlessly." These antonyms all suggest that the individual prioritized their own interests or desires over those of others or failed to consider the long-term implications of their behavior.