I'll try, but not 100% sure [emoji] undo is un (to reverse) + do (something that has been done) = "to reverse what has been done", "to reverse an action". untie = to release from a knot (like neckties) unfasten = to release from anything locked in by & mechanism (like belts) unbind = to release anything that have been held together by wrapping (like hands wrapped with rope) unhitch = to release things that are hooked or caught onto each other (like thumbs "hitched" from front pockets of pants) Examples: I can't *undo my mistake. Can you *untie your own shoes? Do not *unfasten your safety belts during the rollercoaster ride! Please *unbind these old bandages wrapped around my arm so I can replace them with clean ones. The officer finally *unhitched the man's car from his tow truck. You can probably replace untie, unfasten, unbind, and unhitch with undo and it will still kinda make sense. But I think not the other way around.