Scariest, a bumpy flight (9)
I believe the answer is:
staircase
'flight' is the definition.
(a flight of stairs)
'scariest a bumpy' is the wordplay.
'scariest a' anagrams to 'STAIRCASE'.
However, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for staircase that I've seen before include "Situation of flight" , "It's Caesar (anag.)" , "Route between floors" , "A group of linked canal locks" , "Set of steps" .)