Powerful steroids hidden in coat? Quite the opposite! (6)

I believe the answer is:

ulster

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'coat? quite the opposite' is the definition.
I can't judge whether this definition defines the answer.

'powerful steroids hidden' is the wordplay.
'hidden' indicates a hidden word.
'ULSTER' is hidden in the letters of 'powerful steroids'.

'in' is the link.

Can you help me to learn more?

(Other definitions for ulster that I've seen before include "Cloak for an Irish province" , "Area of Ireland" , "Region of Ireland" , "old province" , "Loose overcoat - result (anag)" .)

I've seen this clue in The Telegraph.

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