Pretty loud music (4)
I believe the answer is:
fair
'pretty' is the definition.
(both can mean beautiful or attractive)
'loud music' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'music' becomes 'air' (air is a kind of music).
'f'+'air'='FAIR'
(Other definitions for fair that I've seen before include "Women are known as the ... sex" , "Just - blonde - outdoor entertainment" , "Just right" , "Beautiful like maiden of old" , "... enough! - that's reasonable" .)