prep·py I. noun orprep·pie\ˈprepē\ (pluralpreppies) Etymology:prep + 4-y, -ie 1.: a student at or a graduate of a preparatory school 2.: a person deemed to dress or behave like a preppy II. adjective orpreppie (-er/-est) 1.: relating to, characteristic of, or being a preppy 2.: relating to or being a style of dress characterized especially by classic clothing and neat appearance • prep·pi·ly\ˈprepə̇lē \adverb • prep·pi·ness\ˈprepēnə̇s, -pin- \noun