Shifted meanings: nice and egregious
Many of the words that have been in the English language for more than a few hundred years have shifted their meaning somewhat. The first meaning of the word secretary was exactly what it looks like it should be – someone who keeps secrets. And similarly, principal meant ‘of or belonging to a prince’ well before it was applied to the headmaster of a school.
English is a living, breathing language – and as such, it is only natural for its words to move about as they settle and find themselves applied to new uses. Some words manage to turn themselves around completely, as was the case with egregious, which changed from ‘remarkable in a good sense’ to ‘remarkable in a bad sense’. The latter sense probably came about because egregious was being used ironically or sarcastically, as one might say “Oh, excellent” when faced with an unpleasant situation.
There are other words that have changed directions completely over the years, such as nice, which originally meant silly or ignorant. Of course, this use of nice entered the language some 800 years ago – the world is a completely different place, so why shouldn’t a simple four letter word change as well?