Hi Richard,
It seems that I am late to your test. I knew five of the words you listed.
"ALSO, rhythm(s) is the longest English word without any vowel."
"There may be another [one]: syzygy."
Don't forget crwth and cwm!
Whenever there is a syzygy, I like to hike to a nearby cwm and play ethereal music on my crwth... don't you?
Kaj Chieh Shih
Thank you for your good comments.
You are 100% correct about the word rhythm, but I was surprised to learn that there may be another word that meets the definition of being the longest English word without any vowel;
syzygy
noun: the nearly straight-line configuration of three celestial bodies (such as the sun, moon, and earth during a solar or lunar eclipse) in a gravitational system
syz· y· gy | si-zə-jē |