California firm's fake American hullabaloo (9)
I believe the answer is:
cacophony
'american hullabaloo' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'california firm's fake' is the wordplay.
'california' becomes 'ca' (abbreviation).
'firm' becomes 'co' (a firm is a company).
'fake' becomes 'phony' (synonyms).
'ca'+'co'+'phony'='CACOPHONY'
Can you help me to learn more?
(Other definitions for cacophony that I've seen before include "Clamour" , "Loud discordant sounds" , "Din" , "Terrible row" , "Caterwauling" .)