The word "un-ending" means never-ending or infinite, and its antonyms are words that denote an end or conclusion. Antonyms of "un-ending" are terminable, finite, limited, bounded, completing, finishing, and stopping. Something that is limited has a specific time frame, while something that is finite has an end in terms of quantity. Completing and finishing are words used to indicate that a task has been done. Bounded implies that something has boundaries or limits. Finally, stopping means that something comes to an end. Using these antonyms, it is possible to convey a sense of completion, closure, and finality in any given situation.