This adjective means self-controlled or disciplined—exercising mastery over one's desires, impulses, and appetites. Titus 1:8 lists it among qualifications for elders: they must be self-controlled, upright, holy, and disciplined. Classical Greek used it for those who had power over themselves, masters of their passions. The term emphasizes strength of character that restrains destructive impulses. Leaders must model the self-discipline they call others to practice—controlling tongue, temper, appetites, and ambitions through the Spirit's power.