Fire off loudly in rage (3)
I believe the answer is:
ire
'rage' is the definition.
(ire is anger)
'fire off loudly' is the wordplay.
'off' suggests deleting specific letters ('off' can mean to remove).
'loudly' becomes 'f' (short for forte - 'loud' in music).
'fire' with 'f' taken away is 'IRE'.
'in' is the link.
(Other definitions for ire that I've seen before include "exasperation" , "Hot temper" , "Strong emotion" , "Annoyance, vexation" , "Irritation, anger" .)