opiniaster
n. one who obstinately holds to an opinion

afterwit
n. knowledge gained too late to do any good

jentacular
adj. pertaining to breakfast

hadeharia
n. constant use of the word “hell”

wittol
n. a man who knows of and tolerates his wife’s infidelity

In The King’s English (1997), Kingsley Amis cites an old joke that illustrates the confusing distinction between shall and will:

A swimmer in difficulties was heard to shout, ‘I will drown and nobody shall save me.’ At an inquest on the unfortunate fellow, English jurors wanted a verdict of suicide, Scottish jurors a verdict of death by misadventure, and MacTavish pressed for a rider or footnote rebuking witnesses for making no effort to rescue the victim.

Under the old rule, I shall indicated a prediction and I will denoted a promise or threat. Confusingly, in the second and third persons these meanings were reversed, so that you/she will indicated simple futurity and you/she shall denoted an intention or command. Still more confusingly, old-fashioned speakers of Scottish English reversed this whole understanding of the matter. So while the English jurors thought the swimmer was saying, “It is my intention to drown, and it is my express desire that nobody try to save me,” the Scots took him to say, “I am going to drown and it seems that nobody is going to save me.”

All this has only grown more confused with the popularity of contractions such as I’ll and you’ll, and Americans have generally dispensed with shall and use will for everything. Of the joke, Amis writes, “Nobody tells that one today.”

Some words become famous for their implausibly specific definitions:

ucalegon: a neighbor whose house is on fire
nosarian: one who argues that there is no limit to the possible largeness of a nose
undoctor: to make unlike a doctor

Mrs. Byrne’s Dictionary of Unusual, Obscure, and Preposterous Words, by Josefa Heifetz Byrne, collects examples ranging from atpatruus (“a great-grandfather’s grandfather’s brother”) to zumbooruk (“a small cannon fired from the back of a camel”). My own favorite is groak, “to watch people silently while they’re eating, hoping they will ask you to join them.”

Alas, most of these don’t appear in the magisterial Oxford English Dictionary. Accordingly, in 1981 Jeff Grant burrowed his way into the OED in a deliberate search for obscure words. When he reached the end of A he sent his 10 favorite finds to the British magazine Logophile:

acersecomic: one whose hair was never cut
acroteriasm: the act of cutting off the extreme parts of the body, when putrefied, with a saw
alerion: an eagle without beak or feet
all-flower-water: cow’s urine, as a remedy
ambilevous: left-handed on both sides
amphisbaenous: walking equally in opposite directions
andabatarian: struggling while blindfolded
anemocracy: government by wind
artolatry: the worship of bread
autocoprophagous: eating one’s own dung

“I have been working slowly through ‘B’ and so far my favourite is definitely ‘bangstry’, defined as ‘masterful violence’, an obsolete term that is surely overdue for a comeback.”

(From Word Ways, November 1981.)