The term ‘man’ is not a proper noun; it is a common noun. Proper nouns are specific names for particular people, places, or organizations, and they are always capitalized. For instance, ‘John’, ‘London’, and ‘Microsoft’ are all proper nouns.
On the other hand, ‘man’ refers to an adult male human being in a general sense and does not specify an individual. Therefore, when we use ‘man’, we are speaking about a category rather than a unique entity. So, in summary, while ‘Man’ can be used as a title in certain contexts (like a book or movie title), it is not a proper noun in standard usage.