Fast now, living then
In present-day English, quick is the everyday word for speed. A runner is quick, a reply is quick, a job can be finished in a quick hour. The adjective also covers mental pace: a quick mind, a quick temper, someone quick to notice a mistake. None of that is the oldest job the word had in English.
For centuries it meant alive. That older sense is still sitting in a few fixed corners of the language, which is why the history is recoverable without guesswork. The origin of the word quick is a native Germanic story about life, later bent toward motion and then toward shortness of time.
A home-grown adjective
Old English already had the adjective cwic, with the variants cwicu, cwuc, and cucu. Speakers used it of people, animals, and anything characterized by life. It was not borrowed from French or Latin in the Middle Ages. It is inherited vocabulary, passed into Middle English as quik or quic and only later given the modern spelling.
The initial cw of Old English stood for the same /kw/ sound that later scribes, under French spelling habits, wrote as qu. Northern Middle English often wrote whik or whyk instead. That northern line survives in dialect wick, still used in parts of Yorkshire and neighboring counties for living or lively, and not to be confused with the unrelated place-name wick from Old English wic.
The noun uses grew out of the adjective. In Old English, cwic could already name living persons, often set against the dead. Later English kept that pairing in liturgical language as the quick and the dead, a rendering of Latin vivos et mortuos that Old English had already expressed as cwicum and deadum.
Roots older than English
Behind the Old English form sit reconstructed Proto-West Germanic kwiku and Proto-Germanic kwikwaz, both with the sense alive. Those go back to a Proto-Indo-European adjective built on a root meaning to live. Handbooks do not spell that root identically: some write gwei-, others a more explicit gʷeyh₃- yielding gʷih₃wós. The disagreement is over notation, not over the family.
English did not take the word from Latin or Greek. It shares a distant ancestor with Latin vivus, Greek bios and zoe, Sanskrit jiva, Lithuanian gyvas, Russian zhivoy, Irish beo, and Welsh byw. Those are cognates, not sources.
Nearer relatives keep more of the Germanic shape. Old Saxon and Old Frisian had quik; Old Norse had kvikr, still reflected in Swedish kvick and in Danish and Norwegian kvikk, words that mix liveliness with mental sharpness. Dutch kwiek means sprightly. German keck, from the same stem, drifted toward bold or cheeky rather than fast. Gothic shows a related but not identical form, qius in the singular and qiwai in the plural, which etymologists treat as another Germanic development from the same Indo-European material.
There is no useful prefix or suffix to unpack in the English adjective itself. It is a simple inherited stem. What looks like morphology in later English is compounding, discussed below.
How life became speed
Living things move. From that fact the adjective gathered senses of being lively, stirring, and then rapid. By about 1300, Middle English speakers were using it for swift action. The adverb, the ancestor of quickly, appears in the same period. By the late fifteenth century it could describe a person prompt to perceive or respond. By the 1540s it applied to a process done in little time. Quick-witted is recorded from the 1520s. A quick temper is not high velocity so much as a short fuse: speed of reaction rather than of travel.
Some descriptions already find a figurative stretch toward mental readiness in Old English itself. The large, datable turn toward physical swiftness is still placed around the thirteenth century. The two layers explain a small contrast that English still feels: fast can cover motion of any duration, while quick often implies something sudden or soon over. A starter can be quick; a horse in a long race is more often called fast.
The life-sense did not disappear on a schedule. Around 1200 the adjective could mean sensitive to pain, and it was also used of bright flowers and colors. From the late fourteenth century, the quick named the tender living flesh under a nail. To cut someone to the quick, from the 1520s, takes that living layer figuratively. Middle English used the word of a woman with child once fetal movement could be felt. The verb quicken, from about 1300, first meant to come to life or to give life; an older verb was simply quick, and the earliest intransitive use is often compared with Old Norse kvikna. The sense accelerate is much later, from the 1620s.
Ground that would not stay put could be quick as well. Quicksand is recorded around 1300 as living or moving sand. Old English had cwecesund, but that form may have named a lively stretch of water rather than a sandbank, so the familiar compound is safer dated to Middle English.
Where the old sense still works
A few compounds freeze the first meaning. Late Old English already had cwicseolfor, living silver, a loan-translation of Latin argentum vivum for mercury, whose liquid motion made it seem alive. Dutch kwikzilver and German Quecksilber are parallel formations. Quicklime, from the late fourteenth century, follows Latin calx viva: lime not yet slaked, still chemically live. Quickset, from the fifteenth century, is a hedge grown from live cuttings rather than dead timber.
Those are not folk etymologies. They are the adjective doing its original work, attached to a noun.
The most concrete remnant for a modern speaker is still under the fingernail. Speed is what the word means in almost every sentence now. The history starts one step earlier: not with clocks, but with flesh that is still alive.