The antonyms for the word "leveling off" are many in number, and they vary depending on the context in which the phrase is used. For example, when used to refer to the economy, related terms may include "rising," "surging," and "expanding." In contrast, when one is talking about a decline in activity, antonyms may include "declining," "falling," or "decreasing." In a general sense, the opposite of "leveling off" can be expressed by words such as "accelerating," "growing," or "advancing." Overall, the choice of antonym depends on the particular area of discussion and the intended meaning.