Speech cut? This looks bad, stupid (8)

I believe the answer is:

idiotish

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'speech cut?' is the definition.
The definition suggests an adjective which matches the answer.

'this looks bad stupid' is the wordplay.
I cannot really understand how this works, but
an anagram of 'this' is 'tish' which is located in the answer.
This explanation may well be incorrect...

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I've seen this clue in The Independent.

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