unruffled

Adjective

• (of a body of water) free from disturbance by heavy waves
  • a ribbon of sand between the angry sea and the placid bay
    
  • the quiet waters of a lagoon
    
  • a lake of tranquil blue water reflecting a tranquil blue sky
    
  • a smooth channel crossing
    
  • scarcely a ripple on the still water
    
  • unruffled water
    

• free from emotional agitation or nervous tension
  • the waiters were unflurried and good natured
    
  • with contented mind and unruffled spirit- Anthony Trollope
    

Related words

• Synonyms: 
  placid , quiet , still , tranquil , smooth , unflurried , unflustered , unperturbed