There's been some good discussion in this group about the
merits or otherwise of The Book of the New Sun. Now I'm going to stick my oar in.
C.S. Lewis, who knew a thing or two about writing fantasy and SF said:
"To tell how odd things struck odd people is to tell one
oddity too many"
I think that it is a demonstration of Gene Wolfe's ability that he breaks this rule and (just) gets away with it. There is a sense of living dangerously in the style of the book that is very exciting.
I have tried (on a subsequent reading) checking the 'funny words' in a dictionary. This is a bad idea, because most of the time the words are used as much for their sound and feeling as for their literal meaning. Nevertheless, those words that I found (in Chambers' 20th Century) were correctly used and not flogged to death by repetition like Donaldson.
BTW, Prince Caspian's horse was called 'Destrier'.