Notice one in angry discourse exuding heat? (7)

I believe the answer is:

radiant

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'angry discourse exuding heat?' is the definition.
I can't judge whether this definition defines the answer.

'notice one in' is the wordplay.
'notice' becomes 'ad' (both can mean an advertisement).
'one' becomes 'riant' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' is an insertion indicator.
'ad' put into 'riant' is 'RADIANT'.

Can you help me to learn more?

(Other definitions for radiant that I've seen before include "Brightly glowing" , "'Glorious, shining (7)'" , "Luminous" , "Sending out light, glowing" , "Shining brightly, being at nadir" .)

I've seen this clue in The Sun and The Times.

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