In 1988, traversing synonyms in the Merriam-Webster Collegiate Dictionary, A. Ross Eckler found his way from TRUE to FALSE:

TRUE-JUST-FAIR-BEAUTIFUL-PRETTY-ARTFUL-ARTIFICIAL-SHAM-FALSE

He found his way back again by a different route:

FALSE-UNWISE-FOOLISH-SIMPLE-UNCONDITIONAL-ABSOLUTE-POSITIVE­-REAL-GENUINE-TRUE

He was using the dictionary’s ninth edition; see the article below for his conventions regarding qualifying synonyms. Two more examples:

BAD-POOR-MEAN-PENURIOUS-STINGY-CLOSE-SECRET-FURTIVE-SLY-CUNNING-CLEVER-GOOD

GOOD-CLEVER-CUNNING-SLY-FURTIVE-SECRET-TICKLISH-CRITICAL-ACUTE-SHARP-HARSH-ROUGH-INDELICATE-INDECOROUS-IMPROPER-INCORRECT-WRONG-SINFUL-WICKED-EVIL-BAD

LIGHT-BRIGHT-CLEVER-CUNNING-SLY-FURTIVE-SECRET-HIDDEN-OBSCURE-DARK

DARK-OBSCURE-VAGUE-VACANT-EMPTY-FOOLISH-SIMPLE-EASY-LIGHT

Somewhat related: Lewis Carroll invented word ladders, in which one transforms one word into another by changing one letter at a time:

COLD-CORD-WORD-WARD-WARM

Each intermediate step must itself be an English word. Donald Knuth once used a computer to find links among 5,757 common five-letter English words. 671 of these, he found, were not connected to any other word in the collection. These he dubbed “aloof” — and noted that ALOOF itself is such a word.

(A. Ross Eckler, “Websterian Synonym Chains,” Word Ways 21:2 [May 1988], 100-101.)

C.W. Hooper of Keswick sent this creation to the Strand in August 1901: “It contains all the letters of the alphabet, twenty-six in all. They can be traced with patience. The letter N is the smallest (in the centre), and is the only indistinct one.”

Obscure words from the personal collection of Eric Albert, from a Word Ways article in November 1988:

agroof: face downward
amphoric: resembling the sound produced by blowing into a bottle
benedict: an apparently confirmed bachelor who marries
bort: the fragments removed from diamonds in cutting
callipygian: having shapely buttocks
charette: a period of intense group work to meet a deadline
clishmaclaver: gossip
crepitaculum: the rattle of a rattlesnake
famulus: a magician’s assistant
favonian: like the west wind; mild
formication: the feeling that ants are creeping over one’s skin
fucivorous: subsisting on seaweed
genethliacon: a birthday ode
gobemouche: one who believes everything he is told; literally, “one who swallows flies”
Grimthorpe: to restore a building badly
illth: the reverse of wealth: ill-being
kittly-benders: thin ice that bends under one’s weight
nevermas: a time or date that never comes
nixie: a piece of mail that can’t be delivered because it’s illegibly or incorrectly addressed
quavery-mavery: in an uncertain position
supermuscan: greater than that which is typical of a fly

Albert gives his sources in the article, but I find all the words above in the Oxford English Dictionary.

“A Lowlands Holiday Ends in Enjoyable Inactivity,” a poem by Miles Kington:

In Ayrshire hill areas, a cruise, eh, lass?
Inertia, hilarious, accrues, hélas!

In certain British dialects, the two lines sound the same.

An invertible word made of impossible letters, by Basile Morin:

An emphatic assertion by Douglas Hofstadter:

In 1908, after observing that chump in cursive reads largely the same upside down, the Strand asked for similar specimens and received this:

Writing in the New Yorker in 1949, John Davenport documented a rising language he’d observed among his countrymen. He called it Slurvian. “When Slurvians travel abroad, they go to visit farn (or forn) countries to see what the farners do that’s different from the way we Murcans do things. While in farn countries, they refer to themselves as Murcan tersts, and usually say they will be mighty glad to get back to Murca.”

bean. A living creature.
course. A group of singers.
fiscal. Pertaining to the body, as opposed to the spurt.
line. King of the beasts.
myrrh. A looking glass.
plight. Courteous.
sport. To hold up, to bear the weight of.
wreckers. Discs on which music is recorded for phonographs.

Writing in the Saturday Review in 1970, Cleveland Amory noted a similar phenomenon in the national pastime:

The pisher no longer goes inna wineup, but a stresh. The firss pish is stry one, followed by ball one. Then stry two, ball two, ball three — the full cown. The ba–er fouls one inna the stanns an the cown remains aa three an two. Finally he flies deep to the senner feeler who makes a long run anna fine runnen catch up againssa wall, beyonna warneen track.

Other dialects: Australia, Baltimore, Canada, Texas.

Some personal names used in the land moiety of the Miwok people of Northern California, listed in Brian Bibby’s Deeper Than Gold: Indian Life in the Sierra Foothills, 2005:

akaino: bear holding its head up
engeto: bear bending its foot in a particular manner while walking
esege: bear showing its teeth when cross
etumu: bear warming itself in the sun
sutuluye: bear making noise climbing up a tree
hateya: bear making tracks in the dust
katcuktcume: bear lying down with paws folded, doing nothing
laapisak: bear walking on one place making ground hard
lilepu: bear going over a man hiding between rocks
mo’emu: bears sitting down looking at each other
peeluyak: bear flapping its ears while sitting down
sapata: bear dancing with forefeet around trunk of a tree
tulmisuye: bear walking slowly and gently
utnepa: bear rolling rock with foot when pursuing something
yelutci: bear traveling among rocks and brush without making noise
notaku: growling of bear as someone passes
tulanu: two or three bears taking food from one another
semuki: bear looking cross when in its den
molimo: bear going into shade of trees
tcumela: bears dancing in the hills

Edward Winslow Gifford gives another list in Miwok Moieties, 1916.

What do you call a person from Connecticut? Today we’d call them a Connecticuter or a Connecticutian (or, colloquially, a Nutmegger), but in a 1987 address etymologist Allen Walker Read announced that he’d also found these options:

• Connecticotian, used in 1702 by Cotton Mather
• Connecticutensian, used in 1781 by historian Samuel Peters
• Connectican, used in 1942 in a letter to the Baltimore Evening Sun
• Connecticutan, used in 1946 by book reviewer John Cournos
• Connecticutite, used in 1968 by an anonymous reviewer in Playboy

He also found several jocular forms:

• Connecticutie, a pretty girl of Connecticut (used in 1938 by Frank Sullivan of Mrs. Heywood Broun and in 1947 by a journalist about Clare Boothe Luce)
• Connecticanuck, a Connecticut person of French background
• Connectikook, an oddball or eccentric from Connecticut
• Connecticutup, a prankster from Connecticut

“Especially in language, exuberance accounts for much that happens.”

(Allen Walker Read, “Exuberance, a Motivation for Language,” (Word Ways 21:2 [May 1988], 71-74. He gives his documentation in “What Connecticut People Can Call Themselves,” Connecticut Onomastic Review No. 2, 1981, 3­-23. In 1992 he took up the same question regarding “Americans.”)