n.
  - a supreme ruler, especially a monarch.
 - a former British gold coin worth one pound sterling, now only minted for commemorative purposes.
 
adj.
   - possessing supreme or ultimate power. 
▸archaic or literary possessing royal power and status.
 - (of a nation or its affairs) acting or done independently and without outside interference.
 - dated very good or effective.
 
 
  Derivative
  
  Etymology
  ME: from OFr. soverain, based on L. super ‘above’.