Odd ones in law court go back to complain (5)
I believe the answer is:
growl
'complain' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for growl that I've seen before include "Make an aggressive sound" , "threatening sound" , "Hostile animal's sound" , "gruff sound" , "Sound of hostile animal" .)