Military type regularly is harmful before unfinished attack (7)

I believe the answer is:

samurai

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'military type' is the definition.
(I've seen this before)

'regularly is harmful before unfinished attack' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'before unfinished attack' becomes 'rai' (I can't justify this - if you can you should give a lot more credence to this answer).
'is'+'harmful'='isharmful'
The alternate letters of 'isharmful' are 'samu'.
'samu'+'rai'='SAMURAI'

Can you help me to learn more?

(Other definitions for samurai that I've seen before include "Japanese fighter" , "Traditional Japanese warrior" , "Jap. warrior caste" , "Japanese warrior code" , "Member of Japanese warrior caste" .)

I've seen this clue in The Times.

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