To unhook means to disconnect or unfasten something that was attached by a hook or similar fastener. When you unhook a dog's leash from its collar, you're releasing the metal clip that held them together. When someone unhooks a trailer from a truck, they're separating the two vehicles so they can move independently.

The word works for literal hooks, like when you unhook a fish from a fishing line or unhook ornaments from a Christmas tree. But it also applies to other clasps and fasteners: you might unhook your backpack straps or unhook a necklace clasp.

People sometimes use unhook more broadly to mean separating from anything that was connected. If you're playing a video game and need to unhook from it to do homework, you're pulling yourself away from something that had your attention. In this sense, unhooking means freeing yourself from whatever was holding you.