A phylacist is a jailer -- a prison guard. Say you're on a first date. Thoughts of this post are among the many running through your head. "What do you do for a living?" "I'm a phylacist." "Oh..that sounds interesting." "It is!" Too embarrassed to admit they have no idea what you're talking about, your date may assume you work within some very obscure scientific discipline. Then they return home and look it up and it's either "Tough AND into obscure words! Jackpot!" or "Oh my god, they want to lock me up somewhere and hoped I wouldn't realize it until it was too late."
Or, you know, use phylacist to UTTERLY TERRIFY near-strangers. After all, I'm here to write about words, not offer moral guidance. Plus that would be hilarious. Please update me once they have quietly removed you from their list of Facebook friends, you awful human being.
Proceed with caution, however, as phylacist sounds very similar to another obscure word, phylactic, meaning "a prophylactic," which, of course, in colloquial usage, is often applied to products intended to prevent the spread of sexually transmitted disease, as well as unwanted pregnancy. They seemed perfectly charming. Why did they describe themselves as a walking condom? Why is their very existence an impediment to procreation? Do I really want to find out? No. No, I don't.