This is inspired by (for which read: stolen from) Simon Mayo on last week’s Wittertainment podcast. You know what egregious means, right? It’s something that’s shockingly bad. And you’d be bang on the money. But only in the last 500 years or so. The meaning of egregious has completely changed over time – and not just a little bit like lots of other words. It now means the total opposite of what it did originally.
So, according to the OED in 1534, ‘egregious’ was a positive word which meant ‘remarkably good’. Etymology-wise, it’s made up of the Latin prefix ‘e-‘ which means ‘out of’, ‘grex’ for ‘flock’ (see also ‘segregate ‘, ‘aggregate’ and ‘congregate’) and then the English adjective suffix ‘-ous’ which means ‘full of’. So it literally meant to stand out from the flock (or crowd). But less than 40 years later, people were using it in the negative way we’re familiar with now. Why? Well, it looks like it all comes down to the fact that English people like to take the piss. The only explanation I can find is that people started using it sarcastically, and eventually the second meaning stuck. Typical.