The Oxford Thesaurus An A-Z Dictionary of Synonyms - sedateadj.

1) composed, serene, peaceful, calm, tranquil, cool, collected, even-tempered, detached, imperturbable, unruffled, undisturbed, unperturbed, controlled, placid, grave, serious, sober, solemn, Colloq unflappable: Despite all the turmoil round her, Sarah remained quite sedate. 2) dignified, decorous, refined, formal, stiff, staid, proper, strait-laced, prudish, fussy, prim, conventional, old-fashioned: Donald prefers a sedate waltz to boogying and jiving.