King handily dismissing son in a deplorable way (8)

I believe the answer is:

ruefully

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'king handily dismissing son' is the definition.
I can't judge whether this definition defines the answer.

'deplorable way' is the wordplay.
'deplorable' becomes 'rueful' (I've seen this in another clue).
'way' becomes 'ly' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rueful'+'ly'='RUEFULLY'

'in a' acts as a link.

Can you help me to learn more?

(Other definitions for ruefully that I've seen before include "Loaded with regret" , "Contritely, remorsefully" , "Sorrowfully" , "In a regretful manner" , "In a wryly regretful way" .)

I've seen this clue in The Independent.

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