Antonyms for the phrase "serving purpose" can be expressed as being pointless, useless, ineffective, inefficient, aimless, purposeless, unproductive, unavailing, futile, or unsuccessful. These words describe a situation where an action or object is not fulfilling its intended purpose, which can lead to disappointment or frustration. For example, a tool that was designed to use in a particular situation may not be serving its purpose if it cannot perform the task it was created for. Similarly, a plan or strategy can be considered purposeless if it does not achieve the desired outcome. As a result, it is essential to evaluate the effectiveness of our actions and tools to ensure they are serving their intended purposes.