There are several synonyms for the phrase "in vain," which means that someone's efforts have been unsuccessful or useless. Other terms to describe the same situation include fruitless, pointless, unsuccessful, unproductive, ineffectual, and futile. Each of these words depicts a situation in which someone has worked hard towards a goal, but the outcome was not as intended. Whether it was the result of external forces beyond their control or their actions were insufficient, the end result is the same: they have tried and failed. Using synonyms like these can help to add variety to writing and prevent repetitive language.