Endlessly prolong situation not having to settle in mitigation (11)
I believe the answer is:
extenuation
'mitigation' is the definition.
(I know that mitigation can be written as extenuation)
'endlessly prolong situation not having to settle in' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'in' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for extenuation that I've seen is " Mitigation; palliation".)