Most noisy (7)
I believe the answer is:
loudest
'most noisy' is the definition.
('loud' is associated in meaning with 'noisy')
This is the entire clue.
(Other definitions for loudest that I've seen before include "Least restrained" , "Most deafening" , "Most noisy" , "Noisiest or gaudiest" , "Most flashy" .)