The Collaborative International Dictionary of English v.0.48:

Reposeful \Re*pose"ful\ (r[-e]*p[=o]z"f[.u]l), a.
   Full of repose; quiet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reposeful
    adj 1: affording physical or mental rest; "she spent a restful
           night at home" [syn: restful, reposeful, relaxing]
           [ant: restless, uneasy]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "reposeful":
   at rest, calm, cloistered, comfortable, comfy, commodious,
   contented, convenient, cool, cozy, cushioned, cushiony, cushy,
   dispassionate, dwindling, easeful, easy, ebbing, equable, even,
   even-tempered, even-tenored, friendly, halcyon, homelike, homely,
   homey, hushed, impassive, isolated, levelheaded, lived-in,
   luxurious, moldering, pacific, peaceable, peaceful, placid,
   quiescent, quiet, relaxing, reposing, restful, resting, roomy,
   secluded, sequestered, sequestrated, serene, sheltered, smooth,
   snug, soft, still, still as death, stillish, stilly, stoic, stolid,
   subsiding, tranquil, unagitated, undisturbed, unmoved, unperturbed,
   unruffled, unstirring, untroubled, waning, warm