* Physical appearance: Someone with a physically large head might be seen as arrogant or conceited, even if they aren't.
* Metaphor for arrogance: The idiom likely evolved to metaphorically describe someone who is overconfident, arrogant, or self-important. This is likely because a large head was associated with a larger brain, which in turn was seen as a sign of intelligence and superiority.
Historically, the idiom might have been used to describe:
* People who were believed to be "full of themselves" or "stuck up." This could be because of their wealth, social status, or perceived intelligence.
* Individuals who were considered to be "overblown" or "self-absorbed." This is particularly true in contexts where humility was valued.
Today, "he's got a big head" is still a common idiom used to describe someone who is arrogant or self-important. It is often used humorously, but it can also be a more serious criticism.
It's important to note that the origin of this idiom is not definitively known. However, the connection between a large head and arrogance is likely rooted in cultural perceptions and beliefs that existed in the past.