"Get act" is a phrasal verb which means to start acting appropriately or to improve one's behavior. Some antonyms for "get act" include being careless, unfocused, unproductive, or simply not taking things seriously enough. Another opposite of this verb would be to behave badly, misbehave or act out of line. In essence, antonyms for "get act" imply a lack of responsibility, self-discipline, and commitment to achieving specific goals. To avoid engaging in negative behavior, it is advisable to remain focused, disciplined, and committed to the tasks at hand, which often results in progress and productivity.