introvert

1. (zoology) An organ or other body part that is or can be turned inside out, especially an anterior portion of some annelid worms capable of retraction.Examples: "Important distinctions which obtain amongst the various ‘introverts’ or intro- and e-versible tubes so frequently met with in animal bodies."; "Peanut worms (phylum Sipunculida) are drab-colored bottom dwellers, most of which are less then four inches long. Their body is divided into two sections: the trunk and the introvert. The introvert, the narrow neck-like anterior section, is used as a probe."; "When a peanut worm feeds, it extends and waves its introvert so that the mouth at the tip wanders across the seabed."

2. (psychology) An introverted person: one who is considered more thoughtful than social, with a personality more inwardly than outwardly directed; one who often prefers to have time in non-social situations.Examples: "An Extravert can hardly conceive the necessity which compels the Introvert to conquer the world by means of a system."; "In order to understand the marked contract between Comte's mental attitude during his early years and that of his later life, we must keep in mind Jung's hypothesis of the two psychological types, the introvert and extrovert,—the thinking type and the feeling type."; "All works of the imagination are conceived by men of the introvert type."

3. (figuratively, proscribed) A reserved person.figurativelyproscribed