Merriam-Webster Collegiate Dictionary - sway

 I. noun  Etymology: Middle English sweigh, from sweyen  Date: 14th century  1. the action or an instance of ~ing or of being ~ed ; an oscillating, fluctuating, or sweeping motion  2. an inclination or deflection caused by or as if by ~ing  3.  a. a controlling influence  b. sovereign power ; dominion  c. the ability to exercise influence or authority ; dominance  Synonyms: see power  II. verb  Etymology: alteration of earlier swey to fall, swoon, from Middle English sweyen, probably of Scandinavian origin; akin to Old Norse sveigja to ~; akin to Lithuanian svaigti to become dizzy  Date: circa 1500  intransitive verb  1.  a. to swing slowly and rhythmically back and forth from a base or pivot  b. to move gently from an upright to a leaning position  2. to hold ~ ; act as ruler or governor  3. to fluctuate or veer between one point, position, or opinion and another  transitive verb  1.  a. to cause to ~ ; set to swinging, rocking, or oscillating  b. to cause to bend downward to one side  c. to cause to turn aside ; deflect, divert  2. archaic  a. wield  b. govern, rule  3.  a. to cause to vacillate  b. to exert a guiding or controlling influence on  4. to hoist in place ~ up a mast  Synonyms: see swing, affect  • ~er noun