### Clue: It passes through a prism, a shaft of light overhead (5)
### Answer: SMASH 
 ### Explanation: Definition: overhead
  Hidden(*passes through*) in *priSM, A SHaft*. 
Defn:  An *overhead* hit of the ball, as would be used by 1A and 23A.  ("Overhead" as a noun to equate to "smash"? )