Definitions:

1. a change from one state to the opposite state noun
   • there was a reversal of autonomic function
2. turning in an opposite direction or position noun
   • the reversal of the image in the lens

Synonyms:

• about-face
• black eye
• blow
• change of mind
• flip-flop
• reverse
• reversion
• setback
• transposition
• turn around
• turnabout
• turnaround