Headwear cadet hocks after mobilisation (6,4)

I believe the answer is:

cocked hats

I'm a little stuck... Click here to teach me more about this clue!

'headwear' is the definition.
I can't tell whether this defines the answer.

'cadet hocks after mobilisation' is the wordplay.
'cadet hocks' can be anagrammed to 'COCKED HATS'.
However, I'm not sure how the anagram is indicated.

Can you help me to learn more?

(Another definition for cocked hats that I've seen is " triangles".)

I've seen this clue in The Independent.

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