The phrase "being at disposal" typically implies that someone is readily available or willing to be used for a specific purpose. Antonyms for this term could include "unavailable," "unapproachable" or "inaccessible." These words indicate that someone cannot be easily reached or utilized. Another antonym could be "inflexible," which suggests that someone is unwilling or unable to adjust their schedule or plans to accommodate others. Conversely, "independent" or "self-sufficient" might be seen as opposites of "being at disposal," as they indicate a sense of self-reliance and a lack of reliance on others. Ultimately, the choice of antonym will depend on the context and intended meaning of the phrase being used.