What is the meaning of ‘greased lightning’?

We know what ‘grease’ is. It’s a lubricant that we frequently apply to machinery so that it runs smoothly. When a machine is greased, it runs much faster and smoother. So what would happen if lightning were to be greased? It would move even faster. When you say that someone moves like ‘greased lightning’, you mean he moves very fast. This expression, which originated in the U.S., can also be used to mean ‘powerful’.

*Don’t let the dented body fool you. This little car is greased lightning.

******

“Nothing is often a good thing to say, often a clever thing to say.” — Will Durant