On a dime is a phrase that means a sudden or immediate change of direction or movement. If you're looking for synonyms for on a dime, there are numerous phrases that you can use to convey the same meaning. You can say it changed abruptly, unexpectedly, or suddenly. If you want to be more descriptive, you can use phrases like changing gears, making a U-turn, or doing a 180. Other synonyms for on a dime include taking a sharp turn, stopping on a dime, or changing course. You can also use related terms like pivot, swivel, or twist to describe a sudden change of direction.