sedate in WordNet English dictionary

1. cause to be calm or quiet as by administering a sedative to
   "The patient must be sedated before the operation"
   sedate  calm  tranquilize  tranquillize  tranquillise 
   

1. dignified and somber in manner or character and committed to keeping promises
   "a grave God-fearing man"; "a quiet sedate nature"; "as sober as a judge"; "a solemn promise"; "the judge was solemn as he pronounced sentence"
   grave  sedate  sober  solemn 
   
2. characterized by dignity and propriety
   sedate  staid