Some are rarely used anymore and possibly obsolete, but here is my list of interesting, unique and uncommon words.

Think about how you might use one today!

A gogo	As much as you like; galore; plentiful or without limits.
Ab initio	From the beginning.
Abstergent	Cleansing, scouring or having a detergent effect.
Ad Nauseam	To a sickening or disgusting degree.
Addle	To make or become confused.
Afterclap	An unexpected repercussion.
Agog	Excited and eager to know more or see more.
Bafflegab	Confusing, incomprehensible, or generally unintelligible pretentious language, especially bureaucratic jargon; gobbledegook.
Banal	Something that is so lacking in originality as to be obvious and boring; ordinary; not original.
Barbermonger	Someone who frequents the barber’s shop, or prides himself on being dressed by a barber; a man who is concerned with his clothes and appearance in an affected and excessive way; a dandy.
Battologize	To repeat a word, phrase, mannerism, etc. to an excessive and tiresome degree;
Blatherskite	One who talks foolishly at length (or blathers on and on); rambling nonsensical or inconsequential talk or writing.
Bukh	To brag or talk boastfully.
Borborygmus	the sound of a rumbling stomach; the movement of fluid and gas in the intestinal tract.
Bovine	Having qualities (such as placidity or dullness) characteristic of oxen or cows.
Brabble	Noisy, quarrelsome chatter.
Brusque	Abrupt in manner; blunt.
Bumfuzzle	To confuse or fluster.
Caperlash	Abusive language; to scold.
Carpophagous	Feeding on fruit; fruit-eating.
Cattywampus	(or Catawampus) To be positioned diagonally, askew, or awry; describing something that is not in the correct or expected position; out of alignment.
Chockablock	Very full or crammed full with people or things; brought close together; crowded; jammed.
Churlish	Resembling a churl; vulgar; marked by a lack of civility or graciousness; surly; boorish; rude
Cockamamie	Ridiculous, pointless or nonsensical.
Cogitate	To think deeply about something; meditate or reflect.
Confabulate	To converse informally; chat.
Cornucopia	An abundant, overflowing supply.
Coxcomb	A conceited, foolish dandy; pretentious fop; a man who is too proud of his appearance (or Cockscomb)
Cretin	A person with impaired mental and/or physical development; a stupid person.
Divulgate	To make publicly known or to publish.
Dolosity	Deceitfulness; having hidden malice.
Drivel	Nonsense; boring and unnecessary information; talking stupidly and carelessly; slobbering, drooling or saliva spilling from the mouth or mucus draining from the nose; twaddle, blather, foolishness, gibberish, babble; talking childishly or foolishly; ideas, statements or beliefs that are silly or not true; meaningless talking or thinking.
Echolalia	The imitation sounds made by babies as they learn to talk.
Equiponderate	To counterbalance or offset in weight, force or importance.
Estival	Pertaining to summer.
Feinschmecker	A person who appreciates, enjoys and knows a lot about good food; a gourmet.
Felonious	Wicked or villainous.
Fickle	Likely to change.
Finial D’arbre	A Christmas tree topper.
Flapdoodle	An idea, something said or written, or behavior that is silly or stupid; nonsense.
Flibbertigibbet	A flighty or whimsical person; a gossipy or overly talkative person.
Folderol	Mere nonsense; foolish talk or ideas.
Footle	To talk or act foolishly.
Foozle	To bungle or botch an attempt at something; play clumsily (i.e. in golf).
Frabjous	Wonderful, elegant, superb, joyous, delightful, delicious.
Fractious	Unruly; unwilling to comply.
Fribble	To act in a foolish or frivolous manner; trifle; wasteful.
Gad	To move restlessly or aimlessly from one place to another.
Galactoid	Milky or resembling milk.
Gallimaufry	A hodgepodge; confused medley; jumble.
Gambol	To frolic or skip about, as in dancing or playing.
Gelid	Very cold or icy.
Gnathonic	Excessive flattery; fawning over someone or something.
Gobbledegook	Language that is usually hard to understand
Grame	Anger, sorrow, harm, misery.
Habiliment	Clothes or clothing.
Haboob	A strong desert sandstorm.
Hardihood	Boldness or Daring; Courage.
Harrumph	To clear one’s throat in a self-important manner.
Honeyfuggler	A person who deceives, swindles or cheats someone by talking to them nicely, sweet-talking them, or by using flattery.
Hoodwink	To deceive or trick.
Hornswoggle	To cheat or swindle.
Hotch	To fidget or shift one’s weight from one foot to the other.
Hugger-mugger	In a confused, untidy way that lacks order; secretive or clandestine; disorder or confusion.
Hullabaloo	A clamorous noise or disturbance; an uproar.
Illimitable	Incapable of being limited; limitless; boundless.
Imprimis	In the first place.
Indolent	Wanting to avoid activity or exertion; lazy; slothful.
Invidious	An action or situation likely to arouse or create resentment or anger in others; unfairly discriminating; unjust.
Jackanapes	A person who acts like an ape; not showing proper respect; rude; a tame monkey; an impudent or conceited fellow; a saucy or mischievous child.
Japery	Clowning around; playful or foolish behavior; buffoonery; acting like a fool; engaging in pranks; generally behaving in a silly or frivolous manner; tomfoolery; merriment; monkey business; goofing around and generally acting like a clown.
Jejune	Behavior that is naive, simplistic and superficial; without interest or significance; dull; insipid; juvenile; immature; childish; lacking knowledge or experience; a lack of rewarding or satisfying substance.
Jobbernowl	A Numskull; a Nincompoop; a Block head; a blockish or stupid head; a ludicrous term for the head, usually connoting stupidity.
Joie de Vivre	(pronounced zhwaduh-vee-vruh) “Joy of Living;” a zest for life; a delight in being alive.
Jubilate	To show or feel great joy.
Jujitsu	The use of an opponent’s strengths or one’s own weaknesses to accomplish a goal.
Juke	To make a move intended to mislead or deceive (an opponent); to turn or bend quickly, typically to avoid someone or something.
Kyoodle	To bark or yelp noisily or foolishly.
Lethologica	The inability to remember a particular word or name; sometimes called “tip of the tongue” syndrome.
Lickerish	Eager to consume delicious foods.
Logorrhea	Incessant, wearisome or compulsive talkativeness.
Loogan	A fool or someone considered unsophisticated, sometimes with a derogatory connotation; a mentally ill prisoner; a Fooligan; a newcomer to a group.
Luddite	A person opposed to new technology or ways of working.
Mackle	To blur, as from a double impression in printing.
Mendacious	Habitually telling lies; dishonest; untruthful.
Miscreant	A person who behaves badly or in a way that breaks the law.
Mooncalf	A foolish, absent-minded, idle or freakish person.
Mosey	To wander or shuffle about leisurely; stroll; saunter.
Mugwump	A person who is unable to make up his or her mind on an issue; a person who remains aloof, distant, or not forthcoming about party politics.
Neatnik	A person who is extremely neat about their surroundings or appearance.
Nictate	To wink or blink.
Ninnyhammer	A fool or simpleton, someone lacking good sense or judgment.
Nowhither	To or toward no place; nowhere.
Nugatory	Useless; futile; of no value or importance.
Omnium Gatherum	A collection of miscellaneous people or things.
Opsimath	A person who begins to learn late in life.
Parsimonious	Unwilling to spend money, use resources or use a lot of something; stingy or frugal.
Pecksniffian	Falsely moralistic; holier-than-thou; hypocritical; insincere; sanctimonious.
Pedantic	Someone who annoys others by correcting small errors, caring too much about minor details, or emphasizing their own expertise especially in some narrow or boring subject matter.
Perspicacious	Having keen mental perception and understanding; discerning; having a ready insight into and understanding of things.
Pettifogging	Placing undue emphasis on petty or insignificant details.
Philistine	A person who refuses to see the beauty or the value of art or culture; one of a race of people who lived in the area near the coast of the southeast Mediterranean in ancient times and were often at war with the Israelites.
Phylactery	Two small, square, black leather boxes that contain Torah verses (Scriptures) written on parchment; in Jewish religious practice, Jewish men 13 years of age and older traditionally wear phylacteries during weekday morning prayers on the left arm or the head (Matthew 23:5); protection.
Philistine	A person who is narrow-minded, hostile to or smugly indifferent to cultural values, intellectual pursuits, and aesthetic refinement, often characterized by a materialistic worldview.
Piffle	Nonsense; trivial, foolish or senseless talk.
Pitapat	With a quick succession of beats or taps.
Pithy	Brief, forceful, and meaningful in expression; full of vigor, substance, or meaning; terse; forcible.
Plebiscite	A direct vote of the qualified voters of a state regarding an important public question.
Poltroon	A coward or craven; an adjective to describe something that is marked by cowardice; sneaky and devious; an idler.
Pollrumptious	Restless, unruly, foolishly confident.
Popinjay	A vain or conceited person, especially one who dresses or behaves extravagantly; a parrot.
Poseur	An insincere person; a person who pretends to be what he or she is not; a person who attempts to impress others by assuming a fake manner, degree of elegance, sentiment, etc., other than their true one.
Pugilist	Someone who is inclined to or eager to fight.
Puzzlewit	A stupid person.
Quakebuttock	Someone who lacks the courage to do or endure dangerous or unpleasant things; a coward.
Querulous	Complaining in a petulant or whining manner.
Quidnunc	A person who seeks to know all the latest news or gossip; an inquisitive, nosey or gossipy person; a busybody.
Rapacious	Aggressively or excessively greedy or grasping; ravenous; usually in a selfish way.
Repine	To feel or express sadness or discontent; to complain; To be fretful or low-spirited through discontent.
Ripsnorter	a person or thing that is strikingly active, remarkably good, forceful, exciting, wild, rambunctious, extraordinary; a humdinger.
Rubberneck	To look about or stare with great curiosity.
Salmagundi	a general mixture; a potpourri; a miscellaneous collection.
Samara	The winged fruit of maple and elm trees; sometimes referred to as helicopters.
Sardonic	Bitter or scornful laughter; disdainfully or skeptically humorous; derisively mocking; humorous in an unkind way that shows you do not respect someone or something.
Saturnine	A slow, gloomy, moody, mysterious person or thing; sluggish in temperament.
Scrimshank	To avoid one’s obligations or share of the work.
Scrofulous	Morally tainted, contaminated and corrupt.
Scurrilous	Making or spreading scandalous claims about someone with the intention of damaging their reputation; obscenely abusive; humorously insulting.
Sepulchre	A building or room where a dead person is buried; a place of burial, such as a tomb, grave, vault, or mausoleum; a receptacle for religious relics, especially in an altar; in the Bible, it indicates a burial.
Shilly-shally	To show indecision or hesitation.
Shindig	A large dance, party or other celebration.
Siesta	A Midday or afternoon rest or nap.
Skedaddle	To run away hurriedly or flee.
Snollygoster	A shrewd, unprincipled person, especially a politician.
Sop	A weak-willed or spineless person; milksop.
Spancel	A rope used to prevent an animal from straying.
Splendiferous	Excellent, or very beautiful and special; splendid; magnificient;
Spondulicks	Money; cash; a reasonable amount of spending money; spondoolicks, spondulacks, spondulics, and spondoolics are alternative spellings, and spondoolies is a modern version.
Sprechgesang	(pronounced shprekh-guh-zahng) A style of dramatic vocalization intermediate between speech and song; “speech song.”
Sybilline	Mysterious; cryptic.
Tabula Rasa	Anything existing undisturbed in its original pure state.
Tenebrous	Shut off from the light; hard to understand; murky; dark; gloomy; shadowy; obscure.
Teratoid	Resembling a monster or exhibiting abnormal development, especially in biology, genetics, or medicine.
Tomfoolery	Foolish or silly behavior, act, matter or thing.
Tootle	To move, go, proceed or travel in a leisurely way; a leisurely journey; to play an instrument (like a horn or trumpet) in a casual way.
Trafficator	A blinker or turn signal on a vehicle.
Treacly	Sentimental in a contrived or unrestrained way; excessively sad, emotional, or nostalgic.
Twaddle	Silly, tedious talk or writing.
Ulotrichous	Having woolly, curly or crisp hair.
Ultracrepidarianism	The habit of offering opinions and advice on matters outside of one’s expertise or knowledge; speaking as an authority on a subject when one has limited or no actual knowledge about it.
Unalienable	Not capable of being taken away, denied or transferred.
Vapid	Without liveliness or spirit; dull or tedious; lacking flavor or zest; tiresome; lifeless.
Wamble	To move unsteadily.
Waspish	Readily expressing anger or irritation
Witful	Wise; sage-like; skilled; cunning; ingenious.
Withershins	In a direction contrary to the natural one; contrary; counterclockwise.
Zonked	Exhausted or asleep.