Old English geoguð "youth; young people, junior warriors; young of cattle," related to geong "young," from Proto-Germanic *jugunthi- (source also of 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]

German equivalent of art nouveau, from "Jugend" ("Youth"), the name of a German magazine begun in 1896 + stil "style." See youth (n.) + style (n.).

1560s, from youth + -ful. Old English had geoguðlic. Other words formerly used in the same sense were youthlike, youthly, youthsome, youthy. Related: Youthfulness.

Roman god of youth, personification of iuventas "youth, young person," originally "the age of youth" (from 20 to 40), from iuvenis "young man" (see young (adj.)).

c. 1600, Greek goddess of youth, daughter of Zeus and Hera, wife of Hercules, from Greek hēbē "youth, youthful prime, strength of youth" (legally, "the time before manhood," in Athens 16, in Sparta 18), from PIE *yeg-wa- "power, youth, strength."

Russian communist youth organization, 1925, from Russian Komsomol, contraction of Kommunisticheskii Soyuz Molodezhi "Communist Union of Youth."

"works of a person's youth," 1620s, from Latin iuvenilia, neuter plural of iuvenilis "of or belonging to youth" (see juvenile).

1620s, "state of being young or youthful," from Latin iuvenilitas "youth," abstract noun from iuvenilis "of youth," from iuvenis "young man" (see young (adj.)). Meaning "anything characteristic of youth" is from 1660s; that of "juveniles collectively" is from 1823.

type of cavalryman, 1753, from German Uhlan, from Polish ułan "a lancer," from Turkish oghlan "a youth." For sense evolution, compare infantry.

1811, French jeunesse dorée "gilded youth, rich and fashionable young men," from jeunesse "youth," from jeune "young" (12c.), from Latin iuvenis "young man" (see young (adj.)) + fem. of doré "gilded."