M. John Harrison has the richest vocabulary I think I've ever encountered in an author. His adjectives, especially, come from obscure realms of biology (esp. ornithology), geology, medicine, and what I imagine to be crumbling tomes of cant and argot. The list below are words from his Viriconium stories the epic The Pastel City and mind-boggling A Storm of Wings. Every page was a lexical treasure trove of obscure words but were bon mots one and all, inspiring the imagination with their poetic sound. I kept pen and paper ever at my side as I read.
I share because, if you're reading this, you likely someone who enjoys arcane additions to your lexicon, or you know that I do, so you put up with it.
cresset n. A metal cup, often suspended on a pole, containing burning oil or pitch and used as a torch.
febrile adj. feverish
pullulate v. to breed rapidly, to produce spores
gamboge n. deep yellow color
theophneustia n. divine inspration
occlude v. to prevent passage, to close off
ostler n. one who tends horses
uxorious adj. excessively devoted to one's wife
viscid adj viscous
hispid adj. [Lat.] bristly, hirsute.
hircine adj. [Lat.] of or characteristic of a goat, esp. in smell
lammergeyer n. [Ger. "lamb vulture"]- predatory bird, vulture-like with black feathers. syn. ossifrage. also lammergeier
carious adj. having caries: the decay of bone or tooth
hæmatitic adj. being the color of dried blood
litharge n. yellow lead oxide, rust
nitid adj. bright, lustrous
lampyrine n. glowworm
percipience n. power of keen perception
accipitrine adj. hawklike
abrogate v. [Lat.] To abolish, do away with, or annul, especially by authority.
muculent adj. [Lat.] Slimy; moist, and moderately viscous.
staithe n. Archaic a stage or wharf equipped to load and unload (coal, etc.) from railroad cars into vessels
etiolate v. Botany To become blanched or whitened, as when grown without sunlight.
chivvy v. 1. To vex or harass with petty attacks. 2. To maneuver or secure gradually
culm n. [M.E.] 1. Waste from anthracite coal mines, consisting of fine coal, coal dust, and dirt. 2. a. Carboniferous shale. b. Inferior anthracite coal.
gannet n. [M.E.] Any of several large sea birds of the genus Morus, especially M. bassanus of northern Atlantic coastal regions, having white plumage with black wingtips. Also called solan.
guillemot n. [Fr. "william"] Any of several auks of the genus Cepphus, having black plumage with white markings.
archæan adj. [Gk. "ancient"] Of or relating to the oldest known rocks, those of the Precambrian Eon, that are predominantly igneous in composition.
particulate adj. [Lat.] Of, relating to, or formed of minute separate particles.
crepuscular adj. [Lat. "dark"] 1. Of or like twilight; dim. 2. Zoology Becoming active at twilight or before sunrise, as do bats and certain insects and birds.
glaucous adj. [Gk.] 1. Of a pale grayish or bluish green. 2. Botany Covered with a grayish, bluish, or whitish waxy coating or bloom that is easily rubbed off
induviate adj. Botany of leaves resistant to falling in autumn
catarrhal adj. inflamed, esp. of mucous membranes
albescent adj. [Lat.] Becoming white or moderately white; whitish.
desultory adj. [Lat.] 1. Moving or jumping from one thing to another; disconnected: a desultory speech. 2. Occurring haphazardly; random.
phthisic n. [Gk.] 1. A disease characterized by the wasting away or atrophy of the body or a part of the body. 2. Tuberculosis of the lungs, or any such illness to the lungs.
stridulous adj. [Lat.] 1. Characterized by or making a stridor, ie. shrill grating sound or noise.
hetæra n. pl. hetæræ [Gk. "companion"] An ancient Greek courtesan or concubine, especially one of a special class of cultivated female companions.
Ostler, abrogate and desultory I had merely forgotten, and I have vague memories of once looking up crepuscular. Most of the definitions are from the Unabridged American Heritage Dictionary except I think for staithe, induviate and muculent which had to be found online and lampyrine found searching the Encyclopædia Britannica.