"In the twilight zone" is a phrase commonly used to describe a state of ambiguity or uncertainty, where things are neither entirely one way nor the other. Antonyms for this phrase could include "clear-cut" or "unambiguous," which would suggest that the situation is well-defined and easily understood. Other antonyms might include "secure," "comfortable," or "stable," which would suggest that the situation is not uncertain or unsettling, but rather is known and predictable. Ultimately, the antonyms for "in the twilight zone" are those that suggest a sense of clarity, stability, and understanding, as opposed to ambiguity, uncertainty, and doubt.