The word "un-closes" implies that something is being opened or revealed. The antonym of "un-closes" would be to close or conceal something. Examples of antonyms for "un-closes" include shuts, seals, covers, hides, masks, or obscures. These words express the opposite meaning to un-close or reveal something. For instance, a company might shut down a project that has been un-closed due to budget constraints. Alternatively, a person may want to hide or mask their true feelings after having un-closed their emotions to a friend. Overall, antonyms for "un-closes" describe actions that involve hiding, covering, or concealing information or objects.