Rabbit and white horse featuring in tongue-twister (10)
I believe the answer is:
jawbreaker
'in tongue-twister' is the definition.
I can't judge whether this definition defines the answer.
'rabbit and white horse' is the wordplay.
'rabbit' becomes 'jaw'.
'and' is a charade indicator (letters next to each other).
'white horse' becomes 'breaker' (I can't explain this - if you can you should give a lot more credence to this answer).
'jaw'+'breaker'='JAWBREAKER'
'featuring' is the link.
Can you help me to learn more?
(Other definitions for jawbreaker that I've seen before include "Rock crusher - word that is hard to pronounce" , "heavy-duty machine" , "difficult part of sentence to pronounce" , "Gobstopper" .)