Peril doesn't start in rage (5)
I believe the answer is:
anger
'rage' is the definition.
(I've seen this in another clue)
'peril doesn't start' is the wordplay.
'peril' becomes 'danger' (synonyms).
'doesn't start' means to remove the first letter.
'danger' with its initial letter removed is 'ANGER'.
'in' is the link.
(Other definitions for anger that I've seen before include "Strong feeling of annoyance" , "Nettle" , "Strongly annoy" , "Annoyance, displeasure" , "Wrath, ire" .)