Brown ruler losing by design (7)

I believe the answer is:

tanking

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'brown ruler losing by design' is the definition.
I can't judge whether this definition defines the answer.

'brown ruler' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown).
'ruler' becomes 'king' (king is a kind of ruler).
'tan'+'king'='TANKING'

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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