unhook

verb (used with object)

1. to detach by or as if by releasing a hook: to unhook a tractor from a trailer.
2. to unfasten or open by undoing a hook or hooks: to unhook a door; to unhook a corset.

verb (used without object)

3. to become unhooked.

verb

1. (tr) to remove (something) from a hook
2. (tr) to unfasten the hook of (a dress, etc)
3. (intr) to become unfastened or be capable of unfasteningthe dress wouldn’t unhook