Q. Do you lowercase occupational forms of address like “waiter,” “driver,” “bartender,” and “cook”? It seems that I got different opinions on various websites. Thanks for your input.
A. None of the terms you mention would normally be capitalized in direct address, even when standing in for a name:
Where are you taking me, driver?
Hey, bartender, where’s my drink?
But if the occupation can also be used as a title, capitalization is the norm:
How bad is it, Doctor?
What’s the rush, Captain?
Either convention can be broken, however.
For example, capitalization would make sense for a fictional character known by occupation alone, even if the occupation isn’t also a title—as in the case of the character known as “Driver” in the novels Drive and Driven, by James Sallis (Poisoned Pen Press, 2005 and 2012). And titles that aren’t being used literally are less likely to merit capitalization: What’s up, doc?
For some additional considerations, see CMOS 8.34–37.