The phrase "caught the act" implies that someone has been observed doing something they shouldn't be doing. Antonyms for this phrase could include "had no evidence," "missed the action," or "overlooked the behavior." These phrases suggest that the person in question was not caught in the act and therefore may not have been engaging in any wrongdoing. It's important to note, however, that just because someone hasn't been caught in the act doesn't necessarily mean that they haven't done something wrong. It's always important to investigate any suspicions or concerns and not rely solely on catching someone in the act.