English speakers use shake for a short, violent motion and for several rituals that grew out of that motion. You shake a bottle, a rug, or a fist. You shake with laughter or with fear. You shake hands on a deal, shake your head at a proposal, or try to shake a habit. The noun covers the act itself, a handshake, a wait so brief it is over in two shakes, a milkshake, and, in the plural, a fit of trembling. The everyday verb looks simple. Its history is not.
Native English, not a loan
The origin of the word shake is inheritance from Old English, not a medieval borrowing from French or Latin. Middle English wrote it shaken or schaken. Behind that stands Old English sceacan, also spelled scacan. It belonged to the sixth class of strong verbs: the past tense was scoc, the past participle scacen. Those forms are why modern English still says shake, shook, shaken instead of a regular shaked.
Standard dictionaries place the verb in English before the twelfth century. It is already part of the Old English poetic vocabulary, including Beowulf, where the senses include rapid vibration and, in some lines, departure. The noun is younger. It is built from the verb, not the other way around.
A Germanic verb with an uncertain older root
Comparative reconstruction sets the older form at Proto-Germanic skakaną, with three related meanings: to swing, to shake, and to escape. Proto-West Germanic skakan carried that inheritance into Old English. The family is easy to see once you look north and across the North Sea. Old Norse skaka survives in Icelandic skaka and Swedish skaka. Danish has skage. Scots keeps schake. Low German has schaken. Dutch schaken can mean to shake and, in older use, to make off or elope — a living echo of the escape sense that the Germanic verb already carried. None of these is the source of the English word. They are siblings.
Whether the Germanic verb itself comes from a still older Indo-European root is unsettled. Some accounts reconstruct Proto-Indo-European (s)keg- or (s)kek-, with a meaning in the area of jumping, stirring, or moving, and they point to possible matches such as Sanskrit khaj, to churn or agitate; Old Church Slavonic skoku, a leap; Welsh ysgogi, to move; and Russian скакать, to jump. Other etymologists judge those links too thin and say there are no certain cognates outside Germanic. A further technical objection is that the reconstructed Germanic consonant does not develop as expected from that root, which has led to suggestions of contamination or of back-formation from an iterative verb skakkōną. The Germanic story is firm. The step before it is a hypothesis. Shock is often discussed in the same neighborhood, as a related motion word, not as the parent of shake.
There is little internal morphology to unpack. Shake is not a prefix attached to a smaller English stem. The complexity is in the conjugation: the vowel change that still marks the past. That pattern is the morphology that matters.
Flight, mixing, and greeting
Old English sceacan was already a wide verb. It could mean to move something quickly back and forth, to brandish a weapon, or to tremble from fever, cold, or fear. It could also mean to go, glide, hurry, or flee. A related noun, sceacdom, meant flight. That second cluster — getting away — is easy to miss if you only know the modern physical sense, but it explains later English uses that have nothing to do with rattling a jar.
By about 1200 the verb could mean to throw something off with a sudden twist. Middle English also used it for dodging a responsibility. The American colloquial sense recorded by 1872, to shake someone or something off, looks like a new extension of the same image: a jolt that leaves the clinging thing behind, perhaps with a horse in mind. Around 1300 the earth itself can shake in an earthquake, and a person can shake the head from side to side to refuse. Early in the fourteenth century the verb takes a person as object: to seize and shake. Late in that century cooks shake a container to mix what is inside, and the figurative sense of weakening something by making it unstable is in place. Shaken faith is that late medieval idea, still current.
Greeting, gambling, and music added more specialized uses. To shake hands as a salute is recorded from the 1530s; the handshake as a noun appears by 1712. Seventeenth-century English could shake a heel or a foot to mean dancing, and shake an elbow to mean throwing dice. In the same broad period, to shake one’s ears was a rustic way of saying to bestir yourself, modeled on an animal waking. A musical shake is a trill: a note made to quiver.
The noun starts in the mid-fourteenth century as a charge or onrush, then a hard shock, then the act of shaking, then an irregular vibration. By the early nineteenth century a shake can be a moment so short it is over before you finish the gesture; American speech later made that image concrete as two shakes of a lamb’s tail. The dismissive phrase no great shakes, already used by Byron in 1816, may come from a poor throw of the dice. Fair shake for an honest deal is American English from about 1830. The drink called a shake, clipped from milkshake, is attested by 1911.
The past that did not regularize
The conjugation is the clearest fossil. Modern shook is still the old past scoc, only respelled. That irregular form remembers a Germanic verb that meant both to agitate a thing and to get clear of it. English still does both: you shake a bottle, and you shake a pursuer.