Full of oneself

Origin

The phrase "full of oneself" paints a vivid, almost comical, picture of a person so bloated with self-importance that there's no space left for humility, empathy, or even basic common sense. While its exact birth certificate is lost to time, the idiom likely emerged from the natural human tendency to describe internal states with physical metaphors. To be "full" implies being packed to capacity, leaving no room for anything else. When applied to the self, it suggests an ego that has expanded to fill every available crevice of one's being, metaphorically pushing out any consideration for others. This imaginative idiom distills the essence of arrogance into a memorable and easily understood image, suggesting a person literally overflowing with their own perceived greatness.