The antonyms for the word "more featherbrained" are logical, intelligent, smart, astute, sensible, prudent, shrewd, clear-headed, level-headed, and wise. These words stand in opposition to the idea of being careless or impractical, which is the opposite of featherbrained. Someone who is logical makes rational decisions based on facts and evidence. An intelligent person is knowledgeable and able to comprehend complex ideas. A prudent individual exercises good judgment and caution in their decisions. Being clear-headed implies a sober and rational mind. On the other hand, featherbrained implies acting without much thought. Therefore, these antonyms represent qualities of sound judgment, wisdom, and rationality.