What is another word for labor in vain?
Pronunciation: [lˈe͡ɪbəɹ ɪn vˈe͡ɪn] (IPA) 
There are several synonyms for the phrase "labor in vain," including "fruitless effort," "futile work," "pointless toil," and "wasted energy." All of these phrases convey the same message - that one's labor or effort is ultimately for naught. When we say that someone is laboring in vain, we mean that their work or effort is not yielding the desired result. It can be frustrating when we work hard and invest our time and energy into something, only to find that it was all for nothing. However, it's important to remember that failure is a normal part of life, and we can always learn from our mistakes and try again.
