Antonyms for the word "more unboastful" include boastful, showy, conceited, arrogant, vain, immodest, proud, pompous, and egotistical. These words embody the exact opposite of what it means to be unboastful. A person who is boastful brags excessively about their accomplishments and is self-centered in their view of the world. They seek attention and praise from others, whereas an unboastful person is humble, kind, and modest in their approach. Being unboastful implies that one is not inclined to brag or show off their abilities, but instead prefers to let their actions speak for themselves.