The phrase "are in vain" describes a situation where efforts, actions, or work have been undertaken without any fruitful outcome or result. The antonyms for this phrase would be "succeed," "yield results," "achieve goals," and "be fruitful." Other antonyms include "effective," "productive," "successful," "rewarding," and "fruitful." These words indicate a positive outcome that validates the efforts and hard work put in. Conversely, the words "futile," "ineffective," "inept," "useless," and "fruitless" illustrate that the actions taken have not delivered the expected outcome. Using these antonyms can help express a more specific and positive message about the success and effectiveness of actions undertaken.