Bounce backwards and forwards (3)

I believe the answer is:

bob

I'm a little stuck... Click here to teach me more about this clue!

'bounce' is the definition.
(I've seen this in another clue)

I don't understand how the rest of the clue works.

(Other definitions for bob that I've seen before include "Old coin for Robert" , "Move up and down like Robert" , "money once" , "Curtsy quickly" , "Hairstyle cut shortly and evenly all round" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.