Use it in a sentence!

Obscurantism
     noun
     opposition to the increase and spread of knowledge. deliberate obscurity or evasion.
The current badministration clumsily practices obscurantism. The Trump Greed and Sleaze Syndicate would all be in jail now if the king of obstructionists, McConnell, and the rest of the Republi/Fascists weren’t criminally covering for them.

Viator
     noun
     a wayfarer; traveler.
Ten and I were happy viators, taking two and a half weeks to cross this vast country.

Fantods
     noun
     a state of extreme nervousness or restlessness; the willies; the fidgets (usually preceded by the).
Every day that I wake, finding that, yes, the Tangerine Tyrant is still the president of these pathetic and now terroristic Un-united States, I develop a nasty-ass case of the screaming fantods.

Plumbeous
     adjective
     resembling or containing lead; leaden.
Sounds more like how you’d describe a thick, sweet and gooey Christmas pudding. Ya know: The dessert was positvely plumbeous!

Isolato
noun
     a person who is physically or spiritually isolated from their times or society.
     The rare English noun isolato comes directly from the Italian adjective and noun isolato “isolated; an isolated person.”
Dunno ‘bout you but this sounds way more like a desert to me. As in:
After a sumptuous repast – mushroom, sweet potato quiche followed by spicy eggplant curry and an awesome zucchini alfredo – Jen broke out the lemon isolato.

Yes, I do seem to have cakes and other sweets on the brain this morning. Possibly I’m going through Fratelli-withdrawal. Never a good thing.

Metathesis
     noun
     the transposition of letters, syllables, or sounds in a word, as in the pronunciation aks for ask. 
OR
June’s dissertation was ultra self-referential. Her thesis was all about how she felt, what habits and experiences she developed while writing it. It wasn’t a treatise or monograph on anything but itself. How meta! I betcha the committee loves it.

Knackered
     adjective
     exhausted; very tired.
It took me two full weeks to recover from our long cross country journey. Both of us were blindingly knackered.

Impedimenta
     plural noun
     baggage or other things that retard one’s progress, as supplies carried by an army.
My laptop and back up drives – my chronic impedimenta.

Nadir
     noun
     the lowest point; point of greatest adversity or despair. 
As much as I’d like, I can’t afford to sink into a nadir of hopelessness. None of us can. We must fight back until these enemies of humanity are vanquished.

Fool
     noun
     In British Cookery, this is a dish made of fruit, scalded or stewed, crushed and mixed with cream or the like: gooseberry fool.
Huh, I did not know this – how cool.
The current occupier of the WH would count as both kinds of fool if not for his obvs sour and spoiled to the point of poisonous nature.

Anthophobia
     noun
     an abnormal fear of flowers
"Queen Elizabeth I is said to have been terrorized by roses, a subcategory of anthophobia, a generalized fear of flowers."
~ Marianne Szegedy-Maszak, “Conquering Our Phobias: The Biological Underpinnings of Paralyzing Fears,” U.S. News & World Report, December 6, 2004

Vade mecum
     noun 
     something a person carries about for frequent or regular use.
A vade mecum in English is something, especially a book or manual, that a person carries about for consulting. The English phrase comes from the Latin phrase vāde mēcum “go with me.”

Saying “I need to consult my vade mecum before I give my thoughts on this” sounds WAY more intellectual and cool than saying, “Hold up, I gotta google it on my tinyphone.”

Flimflam
     verb
     to trick, deceive, swindle, or cheat.
Trump flimflammed so much of the electorate out of their best self interests.

Fopdoodle
     noun
     A fool; an insignificant wretch.
I want that idiot, that flimflam man masquerading as president to become infinitesimally inconsequential. I want nothing more than for him to be widely regarded as the cheesiest of fopdoodles. He should be all alone – locked away in one those cages where he keeps his stock of immigrant children . Crowds will visit weekly to point and laugh.