v.
   - move slowly or rhythmically backwards and forwards or from side to side.
 - cause to change in opinion, action, etc.; influence.
 - literary rule; govern.
 
n.
  - a rhythmical movement from side to side.
 - influence or rule.
 
 
  Phrase
  
    
      - hold sway
 have great power or influence. 
    
   
  Etymology
  ME: rel. to Low Ger. swājen ‘be blown to and fro’ and Du. zwaaien ‘swing, walk totteringly’.