Reg Bradey will be upset, old man (9)

I believe the answer is:

greybeard

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'old man' is the definition.
(I know that old man can be written as greybeard)

'reg bradey will be upset' is the wordplay.
'reg bradey' anagrams to 'GREYBEARD'.
Though, I am unsure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for greybeard that I've seen before include "Sage" , "Old man" .)

I've seen this clue in The Irish News.

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