Ground brat with sterner announcement? (5,5)

I believe the answer is:

terra firma

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'ground' is the definition.
(I know that ground can be written as terra firma)

I can't explain the rest of the clue.

(Other definitions for terra firma that I've seen before include "Solid ground" , "Hard ground" , "Solid earth (Latin)" , "Solid earth - dry land" .)

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

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