How I love this word! It has a satisfyingly Latinate vibe, and is delightful to speak out loud. Here’s the definition, courtesy of my indispensable Chambers Dictionary app:
Come on, folks, let’s all use it as much as we can in the days to come. We should all say things like, “‘Downton Abbey’ is just so much retrogressive pabulum, darling. Let’s watch ‘Breaking Bad’ instead”.