Loud anger and passion (4)
I believe the answer is:
fire
'passion' is the definition.
(I know that fire is a type of passion)
'loud anger' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'anger' becomes 'ire' (ire is intense rage).
'f'+'ire'='FIRE'
'and' acts as a link.
(Other definitions for fire that I've seen before include "Sack; conflagration" , "... or combustion" , "Set light to; shoot" , "Flames; passion" , "Dismiss; bake in a kiln" .)