The phrase "waste one's case" refers to spending time, effort, or resources on an endeavor that is likely to fail or is not worth pursuing. Some antonyms for this phrase could include "make progress," "achieve success," "yield results," or "advance one's cause." These antonyms imply that a person is making positive strides towards their goal, instead of wasting their time and resources. Other antonyms could include "give up," "abandon," or "lose hope," which signify a person giving up on their goal or giving in to defeat. Ultimately, the antonyms for "waste one's case" involve either progress or surrender, emphasizing the importance of perseverance and determination in achieving success.