英语词源字典 - 在线词源网站

expressionless (adj.)[expressionless 词源字典]: 1831, "giving no expression," from expression + -less. Shelley used it with a sense of "unexpressed" (1819).[expressionless etymology, expressionless origin, 英语词源]
fetch (n.1): "apparition of a living person, specter, a double," 1787, an English dialect word of unknown origin (see OED for discussion).
A peculiarly weird type of apparition is the wraith (q.v.) or double, of which the Irish fetch is a variant. The wraith is an exact facsimile of a living person, who may himself see it. Goethe, Shelley, and other famous men are said to have seen their own wraiths. The fetch makes its appearance shortly before the death of the person it represents, either to himself or his friends, or both. [Lewis Spence, "An Encyclopedia of Occultism," 1920]
Frankenstein (n.): allusive use for man-made monsters dates to 1838, from Baron Frankenstein, character in Mary Shelley's 1818 novel "Frankenstein: The Modern Prometheus." Commonly taken (mistakenly) as the proper name of the monster, not the creator, and thus franken- extended 1990s as a prefix to mean "non-natural." The German surname is probably literally "Franconian Mountain," stein being used especially for steep, rocky peaks, which in the Rhineland often were crowned with castles. The Shelleys might have passed one in their travels. The German surname also suggests "free stone."
Frankenstein is the creator-victim; the creature-despot & fatal creation is Frankenstein's monster. The blunder is very common indeed -- almost, but surely not quite, sanctioned by custom. [Fowler]
heartless (adj.): Old English heortleas "dispirited, dejected;" see heart (n.) + -less. In Middle English with expanded senses "lacking in courage; foolish; listless; half-hearted; sluggish." Sense of "callous, cruel, wanting in kindly feeling" is not certainly attested before Shelley used it in 1816. Literal meaning "lacking a heart, lifeless" (mid-15c.) is rare. Related: Heartlessly; heartlessness. Similar formation in Dutch harteloos, German herzlos.
immutability (n.): 1590s, from Latin immutabilitas, from immutabilis (see immutable).
Nought may endure but Mutability. [Shelley]
national (adj.): 1590s, from Middle French national (from Old French nation), and also from nation + -al (1). As a noun, "citizen of a (particular) nation," from 1887. National anthem first recorded 1819, in Shelley. Related: Nationally.
optimism (n.): 1759 (in translations of Voltaire), from French optimisme (1737), from Modern Latin optimum, used by Gottfried Leibniz (in "Théodicée," 1710) to mean "the greatest good," from Latin optimus "the best" (see optimum). The doctrine holds that the actual world is the "best of all possible worlds," in which the creator accomplishes the most good at the cost of the least evil.
En termes de l'art, il l'appelle la raison du meilleur ou plus savamment encore, et Theologiquement autant que Géométriquement, le systême de l'Optimum, ou l'Optimisme. [Mémoires de Trévoux, Feb. 1737]
Launched out of philosophical jargon and into currency by Voltaire's satire on it in "Candide." General sense of "belief that good ultimately will prevail in the world" first attested 1841 in Emerson; meaning "tendency to take a hopeful view of things" first recorded 1819 in Shelley.
uglification (n.): 1820 (Shelley), noun of action from uglify.
unconventionality (n.): 1849, with reference to Shelley, from unconventional + -ity.
youth (n.): Old English geoguð "youth; young people, junior warriors; young of cattle," related to geong "young," from Proto-Germanic *jugunthi- (cognates: Old Saxon juguth, Old Frisian jogethe, Middle Dutch joghet, Dutch jeugd, Old High German jugund, German Jugend, Gothic junda "youth"), from suffixed form of PIE root *yeu- "vital force, youthful vigor" (see young (adj.)) + Proto-Germanic abstract noun suffix *-itho (see -th (2)).

According to OED, the Proto-Germanic form apparently was altered from *juwunthiz by influence of its contrast, *dugunthiz "ability" (source of Old English duguð). In Middle English, the medial -g- became a yogh, which then disappeared.
They said that age was truth, and that the young
Marred with wild hopes the peace of slavery
[Shelley]