Headgear with a twisted spike (5)
I believe the answer is:
'headgear with a' is the definition.
I can't tell whether this definition defines the answer.
'twisted spike' is the wordplay.
'twisted' indicates anagramming the letters.
'spike' with letters rearranged gives 'KEPIS'.
Can you help me to learn more?
(Another definition for kepis that I've seen is " French military caps".)