self-possessed self-possessed {adj.} Confident; sure of one self. Before he made his first million, he used to be shy, but afterwards he became very self-possessed. Categories: add yours {adj.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: S Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Discuss