Royal grant treated with disdain (10)

I believe the answer is:

arrogantly

'with disdain' is the definition.

'royal grant treated' is the wordplay.
'treated' indicates an anagram.
'royal'+'grant'='royalgrant'
'royalgrant' anagrammed gives 'ARROGANTLY'.

(Another definition for arrogantly that I've seen is " with haughtiness".)

I've seen this clue in The Times.

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