No longer caring, decided not to keep the appointment (8)

I believe the answer is:

resigned

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'no' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?

I don't understand the remainder of the clue.

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(Other definitions for resigned that I've seen before include "Stopped working" , "Like characters in 5D [WAITING FOR GODOT]" , "Quit" , "without complaining" , "Handed in one's notice to leave" .)

I've seen this clue in the Evening Standard.

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