A knight captivated by end of awful pain (6)

I believe the answer is:

agonal

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'a knight captivated by end of awful pain' is the definition.
I can't judge whether this definition defines the answer.

'a knight captivated by end' is the wordplay.
'knight' becomes 'n' (chess abbreviation).
'captivated by' means one lot of letters goes inside another.
'end' becomes 'goal' (end can mean one's purpose or goal).
'n' inserted into 'goal' is 'gonal'.
'a'+'gonal'='AGONAL'

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I've seen this clue in The Times.

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