"to loosen and throw about in disorder, cause to have a disordered or neglected appearance," 1590s, said originally of the hair, later of the dress. It is chiefly a back-formation from disheveled (q.v.).
genetic disorder causing developmental and intellectual delays, 1961, from J.L.H. Down (1828-1896), English physician; chosen as a less racist name for the condition than earlier mongolism.
"a physical disorder or disease," late 13c., maladie, from Old French maladie "sickness, illness, disease" (13c.), abstract noun from malade "ill" (12c.), from Late Latin male habitus "doing poorly, feeling sick," literally "ill-conditioned," from Latin male "badly" (see mal-) + habitus, past participle of habere "to have, hold" (from PIE root *ghabh- "to give or receive"). Extended sense of "moral or mental disorder, disordered state or condition" is from 14c. Related: Maladies.
disease evidenced by lowness of spirits, sluggishness, indolence, loss of interest in amusements, a wish to be alone, etc., 1765, from hypochondria in its older sense of "melancholy without cause," treated here as a disorder of the body and given the medical ending -osis to denote "a state of disease." The definitions of hypochondria then expanded to include this sense and that has become the usual word for it.
To call the Hypochondriaſis a fanciful malady, is ignorant and cruel. It is a real, and a ſad diſeaſe : an obſtruction of the ſpleen by thickened and diſtempered blood ; extending itſelf often to the liver, and other parts ; and unhappily is in England very frequent : phyſick ſcarce knows one more fertile in ill ; or more difficult of cure. [J. Hill, M.D., "Hypochondriasis," London, 1766]