The antonyms for the word "under-take" are abandon, fail, neglect, give up or surrender. When we undertake something, we commit ourselves to doing it, and it is often accompanied by an expectation of success. However, when we abandon a task, we give up on our initial intentions or goals, and we lack the drive or motivation to continue. Similarly, when we fail or neglect something, we do not accomplish our intended objective. Ultimately, by surrendering, we acknowledge that our efforts have been unsuccessful, and we relinquish control or responsibility for the task at hand. Therefore, we should strive for success and avoid abandoning or neglecting our goals.