sedate

/si-ˈdāt/

Latin sedatus, from past participle of sedare to calm; akin to sedēre to sit

adjective

keeping a quiet steady attitude or pace : unruffled

serious grave solemn sedate staid sober earnest mean not light or frivolous. serious implies a concern for what really matters. grave implies both seriousness and dignity in expression or attitude.

verb

to dose with sedatives