The Collaborative International Dictionary of English v.0.48:
Sedate \Se*date"\, a. [L. sedatus, p. p. of sedare, sedatum, to
allay, calm, causative of sedere to sit. See Sit.]
Undisturbed by passion or caprice; calm; tranquil; serene;
not passionate or giddy; composed; staid; as, a sedate soul,
mind, or temper.
Disputation carries away the mind from that calm and
sedate temper which is so necessary to contemplate
truth. --I. Watts.
Whatsoever we feel and know
Too sedate for outward show. --Wordsworth.
Syn: Settled; composed; calm; quiet; tranquil; still; serene;
unruffled; undisturbed; contemplative; sober; serious.
[1913 Webster] -- Se*date"ly, adv. -- Se*date"ness,
Moby Thesaurus II by Grady Ward, 1.0:
84 Moby Thesaurus words for "sedate":
anesthetize, aristocratic, august, calm, collected, composed,
controlled, conventional, cool, courtly, decorous, demure,
detached, dignified, dispassionate, dope, drug, earnest, entrance,
even-tempered, formal, frowning, fussy, grand, grave, grim,
grim-faced, grim-visaged, hypnotize, imperturbable, imposing,
kingly, long-faced, lordly, lull to sleep, magisterial, magnetize,
majestic, mesmerize, moderate, narcotize, no-nonsense, noble,
old-fashioned, peaceful, placid, prim, princely, proper, prudish,
put to sleep, put under, queenly, refined, regal, rock to sleep,
royal, seemly, serene, serious, sober, sober-minded, sobersided,
solemn, somber, staid, stately, statuesque, stiff, stone-faced,
straight-faced, strait-laced, temperate, thoughtful, trance,
tranquil, undisturbed, unflappable, unperturbed, unruffled,
unsmiling, venerable, weighty, worthy