If you move or look backwards, you move or look in the direction that your back is facing.

If you do something backwards, you do it in the opposite way to the usual way.

You use backwards to indicate that something changes or develops in a way that is not an improvement, but is a return to old ideas or methods.

If someone or something moves backwards and forwards, they move repeatedly first in one direction and then in the opposite direction.

In British English, if you say that someone knows something backwards, you are emphasizing that they know it very well. In American English, you say that someone knows something backward and forward .