The antonyms for the word "un-sticking" are numerous. Some of the most common ones include "sticking", "gluing", "adhering", "bonding", "attaching", and "fastening". These words all imply the act of sticking something together or securely attaching it to something else. In contrast, "un-sticking" suggests the opposite - the process of separating or removing something that is already stuck. Other antonyms for "un-sticking" might include "loosening", "detaching", "disconnecting", "dislodging", or "releasing", depending on the context in which the word is used. Overall, there are many ways to describe the opposite of "un-sticking", depending on what you are trying to convey.