Chief crushed by insult — it makes one see red (4,5)
I believe the answer is:
stop light
'it makes one see red' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'chief crushed by insult' is the wordplay.
'chief' becomes 'top' (synonyms).
'crushed by' means one lot of letters goes inside another.
'insult' becomes 'slight' (I've seen this before).
'top' put inside 'slight' is 'STOP LIGHT'.
Can you help me to learn more?
(Another definition for stop light that I've seen is " makes motorist see red".)