The word "un-snap" denotes the action of detaching or opening something that was previously snapped or closed. Antonyms for this word would include snap, lock, fasten, secure, buckle, clasp, and latch. These words refer to the opposite action of closing or attaching something. For example, one might snap a button on a shirt, lock up a door, fasten a belt, secure a lid, buckle a shoe, clasp a necklace, or latch a window. Knowing the antonyms of "un-snap" can help you select the right words to describe the action you're taking or the object you're interacting with.