What does it mean if a guy calls you missy?

Answer 1

It probably means he's old. Old people are more likely to use that term than young people are.

Answer 2

"Missy" is a term that is often used playfully or teasingly to refer to a younger woman or girl. It can also sometimes be used as a term of endearment or to show a sense of authority or superiority. The intention behind the use of the term can vary depending on the context and the tone in which it is said.