Stillness that is not only silence
English quiet does several jobs at once. As an adjective it can mark a street with little traffic noise, a lake without chop, a person who speaks little, colours that do not announce themselves, or a shop that is not busy. As a noun it names the state itself: the hush of a library, the lull after a storm. As a verb it means to calm something or someone, or, with down, to become less loud. The sense most speakers now treat as central is acoustic: making, or containing, little sound. That ranking is modern. For much of the word’s English life, rest from conflict and motion mattered more than hush.
Borrowed twice, not inherited
The origin of the word quiet is a double borrowing rather than a native Germanic survival. Middle English took the noun from Old French quiete, rest, repose, tranquillity, and the adjective from Old French quiet, while also drawing on Latin itself. The Latin sources are the noun quies, genitive quietis, rest, peace, a lying still, and the adjective quietus, calm, at rest, free from exertion. The Oxford English Dictionary treats both the English noun and the adjective as of multiple origins, partly French and partly Latin. That is a common pattern for words that arrived after the Norman period: French carried the spoken shape, Latin remained available in clerkly and learned writing.
Dating is close but not identical across references. One widely used etymological survey places the noun around 1300 in the sense freedom from disturbance or conflict. The OED’s earliest evidence is a little later, around 1330, in the Middle English romance Arthour and Merlin. The adjective is late fourteenth century, first as peaceable, at rest, not moving or agitated. The verb is Middle English too. The OED cites evidence from before 1398 in a translation by John Trevisa. Formation of the verb is mixed: partly conversion from the English adjective, partly from Late Latin quietare, to calm or to set free. Merriam-Webster groups noun, adjective, and verb in the fourteenth century and dates the adverb to 1573.
A participle, then a family of English words
Latin quietus is the perfect passive participle of quiescere, to rest or keep still. The noun quies is third-declension feminine. Its range in Latin covers sleep and repose, a lull, peace, and stopping work; in some contexts it can even point toward a dream. English quiet is that Latin stem taken over, not a prefix-plus-root native compound. Later English relatives built on the same Latin material include quiescent, quiesce, quietude, quietism, and quietus. Requiem, from requies, rest, belongs here as well. The legal phrase to quiet a title, to free ownership from dispute, keeps the Late Latin sense of setting free, not of lowering volume.
Behind Latin, etymologists reconstruct a Proto-Indo-European root meaning to rest. Spellings differ: *kweie- or *kweiə- in one tradition, *kʷyeh₁- in another. The disagreement is mostly about how to write the reconstruction. Cognates usually listed outside Latin include Old Norse hvild, rest; Old Church Slavonic pokoji, rest; and Iranian forms such as Avestan šaiti-, well-being, and Old Persian šiyatiš, joy. English while and the older adverb whilom are generally assigned to the same distant root on the Germanic side. Wiktionary notes that quiet largely displaced native still in the sense with little or no sound. Still remains, but it now shares the field rather than owning it.
Noise arrives late
Semantic change is stepwise, not a swap of one meaning for another. The noun first named social and political calm. Inactivity and repose appear in the late fourteenth century; absence of noise is recorded around 1400. The adjective begins with rest and peaceableness. Characterized by absence of commotion is dated to the 1510s; private or secret to the 1570s; making no noise only to the 1590s. A quiet conscience or a quiet realm could be at peace long before a quiet engine was a selling point.
The verb’s first English uses were physical: to subdue a sensation, to lessen pain. By the mid-fifteenth century it could mean to make a person or a place quiet. Becoming quiet, intransitive, is much later, dated to 1791, with quiet down from 1851. British English later favoured quieten for the verb; American usage kept quiet.
The same Latin participle split into words English no longer treats as kin. Medieval Latin used quitus, from quietus, for free of debt or war. That path gave English quit, first as exempt or discharged, then as leave or stop, and quite, from the idea of being fully clear. Coy is another doublet: Old French coi, earlier quei, from quietus, first quiet or modest, later shy. Anglo-Norman even used quiet itself for exempt from a payment or discharged from a debt, overlapping quit. Those legal and social senses are easy to miss once the acoustic meaning has taken the centre of the word.
One leftover from the split
The useful reminder is not that quiet comes from Latin, which many English words do, but that one participle produced a set of everyday English items that no longer look related. Quiet kept rest and later added hush. Quit kept the idea of being free of a burden and turned it into departure. Quite kept fullness. Coy kept a social stillness. If you want a date to hold onto, hold the gap between the noun around 1300–1330 and the noiseless adjective in the 1590s: nearly three centuries of English quiet before silence became the headline sense.