The phrase "gave all one's got" implies exerting maximum effort and utilizing all of one's abilities to achieve a goal. Conversely, antonyms for this phrase could be "half-hearted effort," "minimal attempt," or "lackluster performance." These antonyms suggest a lack of commitment or passion towards the task at hand, resulting in subpar results. Alternatively, "lazy approach," "slothful performance," or "neglectful behavior" could also be antonyms for "gave all one's got," indicating a complete disregard for the importance of the task, resulting in failure or disappointment. It is important to always give one's best effort and avoid antonyms that suggest apathy or indifference towards important tasks.