Store up trouble for a sea god (7)

I believe the answer is:

proteus

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'a sea god' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.

'store up trouble' is the wordplay.
'trouble' indicates anagramming the letters.
'store'+'up'='storeup'
'storeup' anagrammed gives 'PROTEUS'.

'for' acts as a link.

Can you help me to learn more?

(Other definitions for proteus that I've seen before include "Greek sea-god" , "Sea god who assumed different shapes to avoid answering questions" .)

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

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