Mellifluous: sweet or musical; pleasant to hear. Limerence: the state of being infatuated or obsessed with another person. Petrichor: a pleasant smell that frequently accompanies rain. Vellichor: the strange wistfulness of used bookstores. Pandiculation: yawning and stretching when waking in the morning.
If you knew the definitions of the five words above without looking them up, you’re several belletristic steps ahead of me. They are bona fide English words that are not commonly used . . . but perhaps should be.
Over my previous career and now as a novelist, I have been cautioned about being too hoity-toity in my vocabulary usage. Put another way, well-intentioned critics have proffered that using too many terms that the average Jack or Jill will probably not understand can detract from the message . . . or even turn some folks away. My proposition is that a) it depends on one’s target audience, and b) a reasonable balance is advisable with respect to vocabulary usage.
If an author’s goal is a fast-read western or romance book that pumps up the reader with six-guns and/or sex (not to mention the desire to sell millions), then one will want to keep the vocabulary relatively simple. If spine-tingling action is secondary to character development, a carefully crafted, innovative storyline and a creative use of language, then the target audience might then be able to handle a more varied vocabulary.
There is also the value for the reader of learning new words. I wouldn’t suggest inserting little-used words for that purpose alone. But it’s legitimate usage if a word is suitable and relatively common to the educated public. The public generally appreciates creative use of language and the challenge of remembering or discovering the meaning of a word.
Put simply, my counsel to authors is to not fear using relatively uncommon words . . . but to be prudent in the frequency of such. If it is a legitimate word that truly says what the writer wants to say, go for the gold.