O.E. sceacan "to vibrate, make vibrate, move away" (class VI strong verb; past tense scoc, pp. scacen), from P.Gmc. *skakanan (cf. O.N., Swed. skaka, Dan. skage "to shift, turn, veer"). No certain cognates outside Gmc., but some suggest a possible connection to Skt. khaj "to agitate, churn, stir about," O.C.S. skoku "a leap, bound," Welsh ysgogi "move," and ult. to PIE *(s)keg-. To shake hands dates from 1535. Shaky "insecure, unreliable" (of credit, etc.) is from 1841. Shake a leg "hurry up" first recorded 1904; shake a heel (sometimes foot) was an old way to say "to dance" (1667). Phrase more _____ than you can shake a stick at is attested from 1818, Amer.Eng. To shake (one's) head as a sign of disapproval is recorded from c.1300. Shaken, of persons, "weakened and agitated by shocks" is from 1641.
c.1380, from shake (v.). As a type of instantaneous action, it is recorded from 1816. Phrase fair shake "honest deal" is attested from 1830, Amer.Eng. The shakes "nervous agitation" is from 1624. Shakeout "business upheaval" is from 1895; shake-up "reorganization" is from 1899. Dismissive phrase no great shakes (1816) perhaps is from dicing.