Is the "South" a proper or common noun? Is it only proper if preceded by the word "the"?
Can be both.
It can be a proper and a common noun. It would be a proper noun if referred to as a region. It would be a common noun if referred to as a direction.
#"People who lived in the South generally supported slavery."#PROPER NOUN
#"After this turn, head south for a few miles."#