Viking manner so despicable (8)

I believe the answer is:

norseman

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

'viking' is the definition.
(I've seen this in another clue)

'manner so despicable' is the wordplay.
'manner so' can be anagrammed to 'NORSEMAN'.
But, I'm not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for norseman that I've seen before include "A viking, perhaps" , "invader" , "one attacking north-east?" , "Scandinavian" .)

I've seen this clue in The Sun.

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