Makes purple as green? (7)

I believe the answer is:

enrages

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'makes purple' is the definition.
Although both the answer and definition are verbs in their -s form, I don't see how one could define the other.

'as green?' is the wordplay.
'as green' anagrams to 'ENRAGES'.
But, I'm not sure how this is indicated.

Can you help me to learn more?

(Other definitions for enrages that I've seen before include "Angers" , "Incenses" , "Infuriates" , "Works up" , "Makes furious" .)

I've seen this clue in The Globe and Mail.

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