After buzzer, you initially fail to make a big splash (9)
I believe the answer is:
bellyflop
'make a big splash' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'after buzzer you initially fail' is the wordplay.
'after buzzer you' becomes 'belly' (I can't explain this - if you can you should give a lot more credence to this answer).
'initially' says to put letters next to each other (some letters go before others).
'fail' becomes 'flop' (flopping is a kind of failing).
'belly'+'flop'='BELLYFLOP'
'to' is the link.
Can you help me to learn more?
(Other definitions for bellyflop that I've seen before include "Less than elegant dive" , "Embarrassing dive" , "unsophisticated dive" , "Bad dive" .)