Area over unfinished main road suffering most (7)
I believe the answer is:
achiest
'area over unfinished main road suffering most' is the definition.
I can't judge whether this definition defines the answer.
'over unfinished main road suffering most' is the wordplay.
'over' means one lot of letters goes inside another.
'unfinished' means to remove the last letter.
'main' becomes 'chief' (synonyms).
'road suffering most' becomes 'ast' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'chief' with its last letter taken off is 'chie'.
'chie' placed inside 'ast' is 'ACHIEST'.
Can you help me to learn more?
(Other definitions for achiest that I've seen before include "suffering most pain" , "most painful" .)