Crazed assailant punched by hard marine (10)

I believe the answer is:

thalassian

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

'marine' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'crazed assailant punched by hard' is the wordplay.
'crazed' is an anagram indicator (a crazy order of the letters).
'punched by' means one lot of letters goes inside another (some letters punch a hole in others).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'assailant' is an anagram of 'talassian'.
'talassian' enclosing 'h' is 'THALASSIAN'.

Can you help me to learn more?

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.