If upheld, such an appeal would lead to dismissal (6)
I believe the answer is:
howzat
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for howzat that I've seen before include "Bowler's appeal" , "Cry of cricket triumph" , "Umpire responds to this" , "An appeal to the umpire?" , "The appeal of cricket?" .)