Modest shaded avenue heading South? Quite the reverse (5)
I believe the answer is:
small
'modest' is the definition.
(thesaurus)
'shaded avenue heading south? quite the reverse' is the wordplay.
I cannot quite understand how this works, but
'south?' could be 's' (abbreviation) and 's' is found in the answer.
'quite' could be 'all' (I've seen this in another clue) and 'all' is found within the answer.
A single letter 'm' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for small that I've seen before include "Not fully grown" , "Social chat" , "Lower middle of the back" , "Insignificant; young" , "Brief" .)