Placid

placid
    adj 1: (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" [syn: {placid}, {quiet},
           {still}, {tranquil}, {smooth}, {unruffled}]
    2: not easily irritated; "an equable temper"; "not everyone
       shared his placid temperament"; "remained placid despite the
       repeated delays" [syn: {equable}, {even-tempered}, {good-
       tempered}, {placid}]
    

Placid \Plac"id\, a. [L. placidus, originally, pleasing, mild,
   from placere to please: cf. F. placide. See {Please}.]
   Pleased; contented; unruffied; undisturbed; serene; peaceful;
   tranquil; quiet; gentle. "That placid aspect and meek
   regard." --Milton. "Sleeping . . . the placid sleep of
   infancy." --Macaulay.
   [1913 Webster]
    

75 Moby Thesaurus words for "placid":
      affliction, at rest, bane, besetment, bother, botheration, calm,
      cloistered, collected, composed, cool, coolheaded, curse, detached,
      disease, dwindling, easy, easygoing, ebbing, epidemic,
      even-tenored, exasperation, halcyon, hushed, impassive,
      inexcitable, infestation, invasion, irenic, irritant, isolated,
      moldering, nuisance, outbreak, pacific, peaceable, peaceful, pes,
      pest, pestilence, philosophical, plague, poised, quiescent, quiet,
      rash, ravage, reposeful, reposing, restful, resting, scourge,
      secluded, self-possessed, sequestered, sequestrated, serene,
      sheltered, smooth, still, still as death, stillish, stilly, stoic,
      stolid, subsiding, tranquil, unagitated, undisturbed, unmoved,
      unperturbed, unruffled, unstirring, untroubled, waning