Like accursed enemies! (5)

I believe the answer is:

sworn

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'like' is the definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for sworn that I've seen before include "Stated on oath" , "confirmed in office" , "Affirmed" , "Given under oath" , "promised" .)

I've seen this clue in the Evening Standard.

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