missy I. \ˈmisē, -si\noun (-es) Etymology:miss (III) + -y (n. suffix) : a young girl : miss < the pious little missy, stiff as a board — Irving Howe > II. adjective Etymology:miss (III) + -y (adjective suffix) : relating to, resembling, or characteristic of a young girl < despite her attempt to seem grown-up, she has a missy primness of manner > III. abbreviation missionary