late 12c., scathen, "to harm, injure, hurt; to cause harm, damage, or loss to," from Old Norse skaða "to hurt, harm, damage, injure," from Proto-Germanic *skathan- (source also of Old English sceaþian "to hurt, injure," Old Saxon skathon, Old Frisian skathia, Middle Dutch scaden, Dutch schaden, Old High German scadon, German schaden, Gothic scaþjan "to injure, damage").
In some sources this is traced to a PIE *sket- "to injure." The Germanic word was seen as cognate with some Celtic formations and Greek a-skēthēs "unharmed, unscathed," but Beekes finds that connection "impossible" on phonetic grounds and Boutkan, agreeing, writes that "The etymon is limited to Celt.-Gmc." and offers no IE etymology.
It survives mostly in its negative past participle unscathed, and in the figurative meaning "sear with invective or satire" (1852, usually as scathing). The latter seems to have developed specifically from the word in the sense of "scar, scorch" used by Milton in "Paradise Lost" (1667).
Knothead also was used as a term in cattle and sheep raising, defined in 1922 as "a type of poorly bred, stunted northern cattle, about the size of yearlings, but with heavy horns indicating that they are older." It turns up, however, in an 1849 petition to the Ohio Legislature, recommending a certain person for a court position, in part because he is a knot-head, which the report of the petition notes is a term of praise for a judge because they are asked to untangle knotty legal questions, but which phrase, it adds, "is believed not to be in use among gentlemen in the north part of the State." [Appendix to the Journal of the Ohio House of Representatives, Session of 1848-9]
"hard aromatic seed of the fruit of a tree found in the East Indies," used as a spice on cookery, c. 1300, note-mug, from Old North French or Anglo-French *noiz mugue, from Old French nois muguete, an unexplained alteration of nois muscade "nut smelling like musk," from nois "nut" (from Latin nux, from PIE *kneu- "nut;" see nucleus) + Latin muscada, fem. of muscat "musky" (see muscat). Probably influenced in English by Medieval Latin nux maga (compare unaltered Dutch muskaatnoot, German muscatnuß, Swedish muskotnöt).
American English colloquial wooden nutmeg "anything false or fraudulent" is from 1827; Connecticut is called the Nutmeg State "in allusion to the story that wooden nutmegs are there manufactured for exportation." [John Russell Bartlett, "Dictionary of Americanisms," 1859]
At a dinner party, the other day, during a little playful discussion of Yankee character, a bland and benevolent-looking old gentleman at my side informed me that he had come to the conclusion that the wooden-nutmeg story was neither more nor less than a mischievous satire. "For," said he, "there would be such an amount of minute carving required to make a successful imitation of the nutmeg, that the deception would hardly pay the workman. For myself, I do not believe the cheat was ever practised." I thanked him in the name of my country for the justice done her, and assured him that the story of the Yankee having whittled a large lot of unsaleable shoe-pegs into melon seeds, and sold them to the Canadians, was also a base fabrication of our enemies. [Grace Greenwood, "Haps and Mishaps of a Tour in Europe in 1853"]
mid-14c., "fluid or juice of an animal or plant," from Old North French humour "liquid, dampness; (medical) humor" (Old French humor, umor; Modern French humeur), from Latin umor "body fluid" (also humor, by false association with humus "earth"); related to umere "be wet, moist," and to uvescere "become wet" (see humid).
In old medicine, "any of the four body fluids" (blood, phlegm, choler, and melancholy or black bile).
The human body had four humors—blood, phlegm, yellow bile, and black bile—which, in turn, were associated with particular organs. Blood came from the heart, phlegm from the brain, yellow bile from the liver, and black bile from the spleen. Galen and Avicenna attributed certain elemental qualities to each humor. Blood was hot and moist, like air; phlegm was cold and moist, like water; yellow bile was hot and dry, like fire; and black bile was cold and dry, like earth. In effect, the human body was a microcosm of the larger world. [Robert S. Gottfried, "The Black Death," 1983]
Their relative proportions were thought to determine physical condition and state of mind. This gave humor an extended sense of "mood, temporary state of mind" (recorded from 1520s); the sense of "amusing quality, funniness, jocular turn of mind" is first recorded 1680s, probably via sense of "whim, caprice" as determined by state of mind (1560s), which also produced the verb sense of "indulge (someone's) fancy or disposition." Modern French has them as doublets: humeur "disposition, mood, whim;" humour "humor." "The pronunciation of the initial h is only of recent date, and is sometimes omitted ..." [OED].
For aid in distinguishing the various devices that tend to be grouped under "humor," this guide, from Henry W. Fowler ["Modern English Usage," 1926] may be of use:
HUMOR: motive/aim: discovery; province: human nature; method/means: observation; audience: the sympathetic
WIT: motive/aim: throwing light; province: words & ideas; method/means: surprise; audience: the intelligent
SATIRE: motive/aim: amendment; province: morals & manners; method/means: accentuation; audience: the self-satisfied
SARCASM: motive/aim: inflicting pain; province: faults & foibles; method/means: inversion; audience: victim & bystander
INVECTIVE: motive/aim: discredit; province: misconduct; method/means: direct statement; audience: the public
IRONY: motive/aim: exclusiveness; province: statement of facts; method/means: mystification; audience: an inner circle
CYNICISM: motive/aim: self-justification; province: morals; method/means: exposure of nakedness; audience: the respectable
SARDONIC: motive/aim: self-relief; province: adversity; method/means: pessimism; audience: the self