"short hair," 1680s; attested 1570s in sense of "a horse's tail cut short," from earlier bobbe "cluster" (as of leaves), mid-14c., a northern word, perhaps of Celtic origin (compare Irish baban "tassel, cluster," Gaelic babag).
The group of bob words in English is of obscure and mostly colloquial origin; some originally were perhaps vaguely imitative, but they have become more or less entangled and merged in form and sense. As a noun, it has been used over the years in various senses connected by the notion of "round, hanging mass," and of weights at the end of a fishing line (1610s), pendulum (1752) or plumb-line (1832). The hair sense was revived with a shift in women's styles starting in 1918 (when it was regarded as a sign of radicalism) and the modern noun meaning "a bobbed hair style" dates from 1920.
In the latter years of the decade [1920s] bobbed hair became almost universal among girls in their twenties, very common among women in their thirties and forties, and by no means rare among women of sixty .... Women universally adopted the small cloche hat which fitted tightly on the bobbed head, and the manufacturer of milliner's materials joined the hair-net manufacturer, the hair-pin manufacturer, and the cotton goods and woolen goods and corset manufacturers, among the ranks of depressed industries. [Frederick Lewis Allen, "Only Yesterday"]
late 14c., sensitif, in reference to the body or its parts, "capable of receiving impressions from external objects, having the function of sensation;" also (c. 1400) in scholastic philosophy, "of or pertaining to the faculty of the soul that receives and analyzes sensory information;" from Old French sensitif "capable of feeling" (13c.) and directly from Medieval Latin sensitivus "capable of sensation," from Latin sensus, past participle of sentire "feel, perceive" (see sense (n.)). Also in early Modern English sencitive.
By 1520s as "of, connected with, or affecting the senses." With reference to persons or mental feelings, "keenly susceptible to external influences," especially "easily touched by emotion, readily wounded by unkindness" (but also "ready to take offense"), by 1816.
What is commonly called a 'sensitive' person is one whose sense-organs cannot go on responding as the stimulus increases in strength, but become fatigued. [James Sully, "Outlines of Psychology," 1884]
The mechanical meaning "so delicately adjusted as to respond quickly to very slight changes or conditions" is by 1857. The Cold War meaning "involving national security" is attested by 1953. Related: Sensitively; sensitiveness.
The purely physical sense, in reference to a living being, skin, etc., "having quick or intense response to sensation," is by 1808; it is preserved in sensitive plant (1630s, also in Shelley's poem), a legume which is "mechanically irritable in a higher degree than almost any other plant" [Century Dictionary].
Marijuana ... makes you sensitive. Courtesy has a great deal to do with being sensitive. Unfortunately marijuana makes you the kind of sensitive where you insist on everyone listening to the drum solo in Iron Butterfly's 'In-a-Gadda-Da-Vida' fifty or sixty times. [P.J. O'Rourke, "Modern Manners," 1983]
As a noun, in mesmerism, "one who is sensitive to hypnotic influence," 1850; later "one in whom the sensitive facility is highly developed, an aesthete" (1891).
c. 1200, Sexun, Saxun, "member of a people or tribe formerly living in northern Germania who invaded and settled in Britain 5c.-6c.," from Late Latin Saxonem (nominative Saxo; also source of Old French saisoigne, French Saxon, Spanish Sajon, Italian Sassone), usually found in plural Saxones, probably from a West Germanic tribal name (represented by Old English Seaxe, Old High German Sahsun, German Sachse "Saxon").
This is traditionally regarded as meaning "warrior with knives" (compare Middle English sax, Old English seax, Old Frisian, Old Norse sax "knife, short sword, dagger," Old High German Saxnot, name of a war-god), from Proto-Germanic *sahsa- "knife," from PIE root *sek- "to cut." But Watkins considers this doubtful.
The word figures in the oft-told tale, related by Geoffrey of Monmouth, who got it from Nennius, of the treacherous slaughter by the Anglo-Saxons of their British hosts:
Accordingly they all met at the time and place appointed, and began to treat of peace; and when a fit opportunity offered for executing his villany, Hengist cried out, "Nemet oure Saxas," and the same instant seized Vortigern, and held him by his cloak. The Saxons, upon the signal given, drew their daggers, and falling upon the princes, who little suspected any such design, assassinated them to the number of four hundred and sixty barons and consuls ....
The OED editors helpfully point out that the murderous shout in correct Old English (with an uninflected plural) would be nimað eowre seax. For other Germanic national names that may have derived from characteristic tribal weapons, see Frank, Lombard. Celtic languages used their form of the word to mean "an Englishman, one of the English race" or English-speaking person in Celtic lands (for example Welsh Sais, plural Seison "an Englishman;" Seisoneg "English;" compare Sassenach).
As an adjective from late 14c. (earlier was Saxish, c. 1200); in reference to the later German state of Saxony (German Sachsen, French Saxe) in central Germany it is attested by mid-14c. Bede distinguished the Anglo-Saxons, who conquered much of southern Britain, from the Ealdesaxe "Old Saxons," who stayed in Germany.
"man who draws attention by unusual finery of dress and fastidiousness manners, a fop," c. 1780, of uncertain origin; attested earliest in a Scottish border ballad:
I've heard my granny crack
O' sixty twa years back
When there were sic a stock of Dandies O
etc. In that region, Dandy is diminutive of Andrew (as it was in Middle English generally). OED notes that the word was in vogue in London c. 1813-1819. His female counterpart was a dandizette (1821) with French-type ending.
Meaning "anything superlative or fine" is from 1786. As an adjective, "characteristic of a dandy, affectedly neat and trim," by 1813; earlier in the sense of "fine, splendid, first-rate" (1792) and in this sense it was very popular c. 1880-1900.
The popular guess, since at least 1827, is that it is from French Dandin, a mock surname for a foolish person used in 16c. by Rabelais (Perrin Dandin), also by Racine, La Fontaine, and Molière, from dandiner "to walk awkwardly, waddle." Farmer rejects this and derives it from dandyprat, an Elizabethan word for "a dwarf; a page; a young or insignificant person," originally (early 16c.) the name of a small silver coin. Both words are of unknown origin, and OED finds the connection of both to dandy to be "without any apparent ground." English dandy was itself borrowed into French c. 1830.
Jack-a-Dandy, or Jack O'Dandy figures in writings from the early 17c. He is listed among other famous Jacks in "Iack a Lent" (1620) and is sometimes defined as an impertinent little man, but other uses are unclear as to sense and in at least one instance from 1620s he is a bogeyman character.
DANDY was first applied half in admiration half in derision to a fop about the year 1816. John Bee (Slang Dict., 1823) says that Lord Petersham was the chief of these successors to the departed Macaronis, and gives, as their peculiarities, 'French gait, lispings, wrinkled foreheads, killing king's English, wearing immense plaited pantaloons, coat cut away, small waistcoat, cravat and chitterlings immense, hat small, hair frizzled and protruding.' [Farmer and Henley, "Slang and its Analogues," 1891]