Seeing red if rule's broken (6)
I believe the answer is:
ireful
'seeing red' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'if rule's broken' is the wordplay.
'broken' is an anagram indicator.
'if'+'rule'='ifrule'
'ifrule' with letters rearranged gives 'IREFUL'.
Can you help me to learn more?
(Other definitions for ireful that I've seen before include "Angry" , "Showing resentment" , "very cross" , "mad" , "Full of wrath" .)