Spring back after impact (6)
I believe the answer is:
bounce
'spring back after impact' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bounce that I've seen before include "Reflect back from a surface" , "Spring back after impact" , "Of a cheque, send back as worthless" , "Exuberance; rebound" , "Rebound (like a cheque)" .)