Now, here’s a scholastic word for an elastic vocabulary. First thing to know about it is that we pronounce the ch as /k/. The rest of the pronunciation should be obvious (stress on the middle syllable, please). The sense is perhaps less so. Is there a savour of challah, or something cataskeuastic about it, or perhaps choleric, pyroclastic, or even cataclysmic? Hmm, rather not. Does it seems like a word that could be chic? Alas! That does not suit it to a t.
But if on the other hand it makes you cataplectic or acts as a laxative, well, congratulations: you have divined it. The word comes from Greek χαλᾶν khalan ‘relax’, from which issued χαλαστικός khalastikos ‘laxative’. So, yup, that Dulcolax you have in the cabinet is a chalastic – never mind the hard stops at front and back of the word /k/ /k/ that would seem to contain the liquid /l/ in the middle. But the other sense of it relates not to intestinal relaxation but to full-body loss of tone: cataplexy or sleep paralysis – in fact, sleep paralysis is sometimes called a post-dormitial chalastic fit. Which, honestly, is a bit of terminology that may induce its object.