"to make a pretense of," 1660s, earlier "to assume the character of (someone)," 1590s; originally in English in a now-obsolete sense of "aim at, aspire to, desire" (early 15c.), from Old French afecter (15c.), later affecter, from Latin affectare "to strive after, aim at, aspire to," frequentative of afficere (past participle affectus) "to do something to, act on, influence" (see affect (n.)). Related: Affected; affecting.
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
[extent] 1530s, "room to act, free play," also literal (1550s), "room to move in, space;" from Italian scopo "aim, purpose, object; thing aimed at, mark, target," from Latin scopus, from Greek skopos "aim, target, object of attention;" also "watcher, one who watches," which according to Watkins is from a metathesized form of PIE *spek-yo-, suffixed form of root *spek- "to observe." Beekes writes that the the old IE root noun (as in Latin haruspex) from *spek- apparently was replaced in Greek by skopos.
It is attested from 1550s as "that which is aimed at or desired," hence "ultimate aim;" the classical sense of "a mark to aim or shoot at" was in English by 1560s but now is obsolete. Hence "object a speaker or writer has in view" (1530s). The sense of "intellectual range, distance the mind can reach" is recorded from c. 1600. By 1590s as "extent in space." By 1830 as "sphere in which some activity operates." Elizabethan scopious "spacious, wide" did not stick.
For sense development, compare expression work the land, Old Norse yrkja "work," but especially "cultivate" (and also "to make verses"); Old Church Slavonic delati "work," also "cultivate." Related: Tilled; tilling.
c. 1300, purpus, "intention, aim, goal; object to be kept in view; proper function for which something exists," from Anglo-French purpos, Old French porpos "an aim, intention" (12c.), from porposer "to put forth," from por- "forth" (from a variant of Latin pro- "forth;" see pur-) + Old French poser "to put, place" (see pose (v.1)).
Etymologically it is equivalent to Latin propositium "a thing proposed or intended," but evidently formed in French from the same elements. From mid-14c. as "theme of a discourse, subject matter of a narrative (as opposed to digressions), hence to the purpose "appropriate" (late 14c.). On purpose "by design, intentionally" is attested from 1580s; earlier of purpose (early 15c.).