Any mechanism or operation that unwinds something.
"The new washing machine features an automatic unwind system for the detergent drawer."
separate the tangles of
"After spending hours trying to separate the tangled headphones, she finally managed to unwind them without breaking any wires."
To separate (something that is wound up)
"After winding the clock tightly all morning, I spent a few minutes carefully unwinding the spring to reset it."
Unwind comes from Middle English and originally meant to unwrap or undo a coil. It is formed by combining the prefix un- with the word for winding something into a spiral.