Course not to be taken by drivers (7)
I believe the answer is:
pathway
'be taken by drivers' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'course not' is the wordplay.
'course' becomes 'path' ('path' can be a synonym of 'course').
'not' becomes 'way' (I can't justify this - if you can you should give a lot more credence to this answer).
'path'+'way'='PATHWAY'
'to' is the link.
Can you help me to learn more?
(Other definitions for pathway that I've seen before include "Walking track" , "route? ..." , "A trodden track" .)