My mother used to rail[1] about Americanisms. I once went through every word which she claimed to be in that category, and found that about half of them (to within statistical error) were originally English words the used of which had died out in Britain but been preserved in America (so their usage was older than ours in about the same amount as the other way round). I don't remember 'faze' being one of them, though, thanks for the information.

[1] I suddenly wondered if 'rail' (in the sense of rant or complain) was an 'imported' word. You can (if you so desire) imagine my relief at finding that its origin is "1425–75; late Middle English railen < Middle French railler to deride < Provençal ralhar to chatter < Vulgar Latin *ragulāre, derivative of Late Latin ragere 'to bray'". Phew! Saved by the dictionary...