Neither sickly nor naughty, which is fine in its own way (4,3,4)
I believe the answer is:
well and good
'neither sickly nor naughty which' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'fine in its own way' is the wordplay.
I cannot really understand how this works, but
'fine' could be 'well' (similar in meaning) and 'well' is present in the answer.
'way' could be 'n' (Compass direction - North) and 'n' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'is' is the link.
Can you help me to learn more?
(Another definition for well and good that I've seen is " fine".)