shake v.

Middle English shaken, from Old English sceacan "move (something) quickly to and fro, cause to move with quick vibrations; brandish; move the body or a part of it rapidly back and forth;" also "go, glide, hasten, flee, depart" (as in sceacdom "flight"); also intransitive, of persons or parts of the body, "to tremble" especially from fever, cold, fear (class VI strong verb; past tense scoc, past participle scacen).

This is reconstructed to be from Proto-Germanic *skakanan "to shake, swing," also "to escape" (source also of Old Norse, Swedish skaka, Danish skage "to shift, turn, veer"). There are said to be no certain cognates outside Germanic, but some sources suggest a PIE root *(s)keg- "to jump, to move" (compare Sanskrit khaj "to agitate, churn, stir about," Old Church Slavonic skoku "a leap, bound," Welsh ysgogi "move"). Also compare shock (n.1).

Of the ground in earthquakes, c. 1300. The meaning "seize and shake" (someone or something else) is from early 14c. From late 14c. in reference to mixing ingredients, etc., by shaking a container. The meaning "weaken, impair" in any respect is from late 14c. on the notion of "make unstable." The meaning "rid oneself of by abrupt twists" is from c. 1200; the modern colloquial use for "get rid of, cast off, abandon" (by 1872, American English) is likely a new extension on the notion of "throw off by a jolting or abrupt action," perhaps with horses in mind. The verb also was used in Middle English as "evade" responsibility, etc.

To shake hands "greet or salute by grasping one another's hands" dates from 1530s. Colloquial shake a (loose) leg "hurry up" is recorded by 1904; to shake a heel (sometimes foot) is an old or provincial way to say "dance" (1660s); to shake (one's) elbow (1620s) meant "to gamble at dice." In 16c.-18c. English, shake (one's) ears was "bestir oneself," an image of animal awakenings. The phrase more _____ than you can shake a stick at "more than you can count" is attested from 1818 (Lancaster, Pa., "Journal"), American English. To shake (one's) head "move one's head from side to side as a sign of disapproval" is recorded from c. 1300.

mid-14c., "a charge, an onrush," from shake (v.). The meaning "a hard shock, concussion" is from 1560s; it is attested from 1580s as "act of shaking, a rapid jolt or jerk one way and then another;" by 1660s as "irregular vibration."

The hand-grip salutation is so called by 1712. A shake as a figure of a brief moment or instantaneous action is recorded by 1816; the exact shake intended is uncertain. OED's 1816 citation is in the shake of a hand and might be partly literal. The noun also meant "a trill in music." The version two (or three) shakes of a lamb's tail (1852) seems to be a U.S. dialect elaboration of the older use, earlier of a sheep's tail (Boston Weekly Globe, March 29, 1843, which identifies it as "a homely adage").

The phrase fair shake "an honest deal" is attested from 1830, American English (Bartlett calls it "A New England vulgarism"). The shakes "nervous agitation" is from 1620s; the sense of "trembling fit; intermittent fever" is by 1782. Shake as short for milk shake is attested by 1911. Dismissive phrase no great shakes (1816, Byron), indicating things of no account, perhaps is from dicing.