"Grups" (From the Start Trek episode "Miri") has entered our vocabulary. My wife sometimes has to remember
not to use it in general conversation.
I recommend using words in context and only explaining them if necessary.
I'm using a lot of Old English words to describe things in my story. I use "galdorcræft" in the first sentence and state the chapel is a quiet place to muster the concentration needed to perform it. Then two sentences later, I pair it with scrying. Between 'cræft', needing concentration, and 'scrying' I'm hoping it will be clear that galdorcræft is magic. I'm not using the word 'magic' in my story at all because it's told in tight third person from my MC's POV and the word 'magic' doesn't exist in his vocabulary.
Anathem is a book people either love or hate because of the masses and masses of made-up vocabulary. I loved it. When I came up for air from being immersed in his worldbuilding I was in awe of how he'd handled defining those words.
Part of it was that he used words we were familiar with to make many of his new words. An Anathem is a sort of combination of Anathema and Anthem. It's a sung rite of throwing someone out.
Part of it was the Main character is secluded in that world's equivalent of a monastery (a 'Math' where people study science) and so new words used by people outside the Maths, or people in other chapters in the Math, have to be defined for him.
Part of it is because the book is a report of what happened and so the MC is explaining to the people he's reporting to terms that might be unfamiliar to them.
And part of it is just using context very well.