Primarily, indignation about fury (3)
I believe the answer is:
ire
'fury' is the definition.
(ire is intense rage)
'primarily indignation about' is the wordplay.
'primarily' indicates taking the first letters.
'about' becomes 're' ('re' means regarding or about).
The first letter of 'indignation' is 'i'.
'i'+'re'='IRE'
(Other definitions for ire that I've seen before include "resentment" , "Irritation, anger" , "exasperation" , "Choler" , "Annoyance, vexation" .)