A portmanteau word combining 'smug' and 'astonished'.

The look of someone who can't believe it's remotely possibly they could ever be wrong (and can't understand why anyone is challenging them). It is a look generally worn when the wearer is entirely wrong but - due to arrogance, ignorance or disdain - refuses to admit it.

A smugstonished look is often worn by MPs and other public figures when questioned by the electorate or the media, by professionals in all industries when talking to people they perceive as 'less qualified' and by the kind of people who can't shut up during otherwise friendly pub conversation.

When you eat dirt for the first time and leave your family to build a shack in the woods