Curse? He'll go red (6)

I believe the answer is:

bloody

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'red' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for bloody that I've seen before include "Gory" , ""____ but unbowed"" , "Cruel, murderous" .)

I've seen this clue in The Guardian.

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