Here are some possibilities:
General:
* Reversal: This is the most common and direct noun form of "reverse." It refers to the act of reversing something.
* Opposite: This noun refers to something that is completely different from the original.
* Inverse: This noun refers to something that is the opposite or reciprocal of the original.
Specific:
* Counteraction: This refers to something that stops or reverses a process.
* Retrograde: This refers to a movement in the opposite direction, especially backward.
* Undo: This is an action that reverses a previous action.
* Rewind: This is the action of moving something backward, especially a tape or recording.
Examples:
* "The team's reversal in fortune came after a series of poor performances."
* "The decision was met with opposition from the community."
* "The inverse of adding is subtracting."
* "The drug's counteraction to the virus was immediate."
* "The retrograde movement of the star was observed by astronomers."
* "I tried to undo the damage, but it was too late."
* "He rewound the tape to listen to the conversation again."
The best noun to use will depend on the specific meaning you want to convey.