The word "comebacking" is not commonly used in the English language and therefore does not have established antonyms. However, some words that can be used in its place are "departing", "fading away", "vanishing", "withdrawing", or simply "leaving". These words indicate the opposite of "comebacking", which refers to a return or resurgence. When a person or thing is not having a comeback, they may instead be experiencing a decline or decrease in popularity, relevance, or performance. Therefore, the antonyms for "comebacking" must be chosen based on the specific context in which it is being used.