Popular use of the word Youth refers to a person who is neither an adult nor a child, but somewhere in between, scientifically referred to as an adolescent and, in most English speaking countries, commonly referred to as a teen or teenager. It is used to identify a particular mindset of attitude, as in "He is very youthful". In various social, political, cultural, and legal contexts, the word "youth" refers to a pre-determined set of experiences, ideals, and perspectives.

Sourced

• Young people are in a condition like permanent intoxication, because youth is sweet and they are growing.
  • Aristotle in Nicomachean Ethics

• "Nature has done well and wisely, in not permitting a man to live forever and in bringing into the world ever new generations. An old person is a used-up machine [... He] has too many dogmas to [...] easily [...] believe in a new truth [...]; too many sympathies and antipathies [...] for him to come to love something unfamiliar; [...] too many habits to be able to settle on new ways. Let us add suspiciousness — the fruit of bitter experiences; a pessimism inseparable from all manner of disappointments; and finally, a general decline of powers from exhaustion [...]."
  • Bolesław Prus, "Oda do młodości" ("Ode to Youth"), 1905.

• It is an illusion that youth is happy, an illusion of those who have lost it; but the young know they are wretched, for they are full of the truthless ideals which have been instilled into them, and each time they come in contact with the real they are bruised and wounded.
  • W. Somerset Maugham, Of Human Bondage (1915)

• Youth are diamonds in the sun, diamonds are for ever.
  • Alphaville, Forever Young (1984).

• YOUTH: The too-brief span wherein the human chassis is factory-fresh, undented and free of corrosion; a pristine condition worshiped by menopausal women in sweatsuits and shrinking men with chestnut-brown toupees, while those who actually possess it are frequently too shallow or despondent to enjoy it.
  • Rick Bayan, The Cynic's Dictionary, 1994.

• Youth cannot know how age thinks and feels. But old men are guilty if they forget what it was to be young... and I seem to have forgotten lately.
  • Dumbledore in Harry Potter and the Order of The Phoenix by J.K. Rowling

• Age is foolish and forgetful when it underestimates youth.
  • Dumbledore in Harry Potter and the Half-Blood Prince by J.K. Rowling

• We must be very careful when we give advice to younger people: sometimes they follow it!
  • Edsger W. Dijkstra, The Humble Programmer, 1972 Turing Award Lecture, Communications of the ACM 15 (10), (October 1972): pp. 859–866

• For the more paart, youthe is rebel,
  Un-to reson & hatith her doctryne.
  • As for the moré part Youth is rebél
    Unto Reasón, and hateth her doctrine.
  • Thomas Occleve, from Frederick Furnivall and Israel Gollancz's three-volume edition of Hoccleve's Works (Early English Text Society, 1892-1925), Line 65, vol. 1, p. 27; modern spelling from Henry Morley (ed.) Shorter English Poems (London: Cassell, 1883), p. 58.

Dictionary of Burning Words of Brilliant Writers (1895)

Reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895).

• The greatest part of mankind employ their first years to make their last miserable.
  • Jean de La Bruyère, p. 623.

• Use thy youth so that thou mayest have comfort to remember it when it hath forsaken thee, and not sigh and grieve at the account thereof. Use it as the spring-time which soon departeth, and wherein thou oughtest to plant and sow all provisions for a long and happy life.
  • Sir Walter Raleigh, p. 623.

• Every stage of life has its own set of manners, that is suited to it, and best becomes it. Each is beautiful in its season; and you might as well quarrel with the child's rattle, and advance him directly to the boy's top and span-farthing, as expect from diffident youth the manly confidence of riper age.
  • Bishop Hurd, p. 624.

• A youth thoughtless! when the career of all his days depends on the opportunity of a moment! A youth thoughtless! when all the happiness of his home forever depends on the chances or the passions of an hour! A youth thoughtless! when his every act is a foundation-stone of future conduct, and every imagination a fountain of life or death! Be thoughtless in any after years, rather than now — though indeed there is only one place where a man may be nobly thoughtless — his death-bed. No thinking should be ever left to be done there.
  • John Ruskin, p. 624.

• Oh thou corrupter of youth! I would not take thy death, for all the pleasures of thy guilty life, a thousand fold. Thou shalt draw near to the shadow of death. To the Christian these shades are the golden haze which heaven's light makes, when it meets the earth and mingles with its shadows. But to thee, these shall be shadows full of phantom-shapes. Images of terror in the Future shall dimly rise and beckon: — the ghastly deeds of the Past shall stretch out their skinny hands to push thee forward! Thou shalt not die unattended! Despair shall mock thee. Agony shall tender to thy parched lips her fiery cup. Remorse shall feel for thy heart and rend it open. Good men shall breathe freer at thy death, and utter thanksgiving when thou art gone.
  • H. W. Beecher, p. 624.

• When we are out of sympathy with the young, then I think our work in this world is over.
  • George MacDonald, p. 624.

Unsourced

• What I lack in youth I make up for in immaturity.
  • Marty Feinberg

• You are too young to be old...
  • Jim Morrison

Unknown

• I find young people exciting. They have an air of freedom, and they have not a dreary commitment to mean ambitions or love of comfort. They are not anxious social climbers, and they have no devotion to material things.
  • Unknown

• You really are only as old as you feel. That's why I'll always be a kid, even after I'm a hundred years old.
  • Anonymous

• I wasted most of my youth worrying about what other people thought about me, and then I realised that other people hardly thought about me at all.
  • Unknown

• There is only one difference between an old man and a young one: the young man has a glorious future before him and the old one has a splendid future behind him: and maybe that is where the rub is.
  • Unknown

• When I was a teenager, I felt that I was just young and uncertain -- that I was a new boy in a huge school, and I would have been very pleased to be regarded as something so interesting as a problem. For one thing, being a problem gives you a certain identity, and that is one of the things the young are busily engaged in seeking.
  • Unknown

• Youth is truly wasted on the young.
  • Unknown

• Youth is the best time to have fun and make as much mistakes as you can so you can learn from them soon before you enter the long twist and turns of adulthood.
  • Unknown

• You can't be old and wise if you were never young and foolish.
  • Unknown