The phrase "got in the act" means that someone was caught doing something, often something they shouldn't have been doing. Antonyms for this phrase would include "avoided detection," "escaped notice," or "remained unnoticed." These antonyms imply that someone succeeded in doing something without getting caught or detected. Other antonyms could include "exonerated," "cleared," or "acquitted," which suggest that someone was investigated but ultimately found innocent of any wrongdoing. Conversely, synonyms for "got in the act" might include phrases like "caught red-handed," "exposed," or "busted," all of which indicate that someone was caught doing something they shouldn't have been doing.