One in no hurry to get treated? (7)

I believe the answer is:

patient

I'm a little stuck... Click here to teach me more about this clue!

'one in no hurry' is the definition.
(I've seen this in another clue)

I can't explain the remainder of the clue.

(Other definitions for patient that I've seen before include "Calm" , "Sufferer" , "Cool" , "one of interest to medics?" , "case for treatment" .)

I've seen this clue in the Evening Standard.

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