Etymology
Advertisement
disorder (v.)

late 15c. (Caxton), "destroy or derange the order of, throw into confusion," from dis- "not" (see dis-) + order (v.). Replaced earlier disordeine (mid-14c.), from Old French desordainer, from Medieval Latin disordinare "throw into disorder," from Latin dis- + ordinare "to order, regulate," from ordo (genitive ordinis) "row, rank, series, arrangement" (see order (n.)). Related: Disordered; disordering.

Related entries & more 
Advertisement
disorder (n.)

1520s, "lack of regular arrangement;" 1530s, "tumult, disturbance of the peace;" from disorder (v.). Meaning "an ailment, a disturbance of the body or mind" is by 1704.

Related entries & more 
psychological (adj.)

1680s, "of or pertaining to the mind as a subject of study;" see psychology + -ical. In early 20c. the sense gradually shifted toward "affecting or pertaining to a person's mental or emotional state." Related: Psychologically. Psychological warfare "use of propaganda, etc., to undermine an enemy's morale or resolve" is recorded from 1940. Psychological moment was in vogue from 1871, from French moment psychologique "moment of immediate expectation of something about to happen."

The original German phrase, misinterpreted by the French & imported together with its false sense into English, meant the psychic factor, the mental effect, the influence exerted by a state of mind, & not a point of time at all, das Moment in German corresponding to our momentum, not our moment. [Fowler]
Related entries & more 
attention deficit disorder (n.)
(abbreviated ADD), introduced as a diagnosis in the third edition of the "Diagnostic and Statistical Manual of Mental Disorders" (1980), from attention in the "power of mental concentration" sense. Expanded to attention deficit hyperactivity disorder ("the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone;" ADHD) in DSM-III (1987).
Related entries & more 
bulimia (n.)
"emotional disorder consisting of food-gorging alternating with purging or fasting, accompanied by morbid concern with body weight and shape," 1976, Modern Latin, from Greek boulimia, "ravenous hunger" as a disease, literally "ox-hunger," from bou-, intensive prefix (originally from bous "ox;" from PIE root *gwou- "ox, bull, cow") + limos "hunger," from PIE *leie- "to waste away."

As a psychological disorder, technically bulemia nervosa. Englished form boulimy, bulimy was used from late 14c. in a medical sense of "morbidly ravishing hunger, disease causing the patient to have an insatiable hunger for food."
Related entries & more 
Advertisement
shambolic (adj.)
1961, apparently from shamble in the sense "disorder" (see shambles), perhaps on model of symbolic.
Related entries & more 
muss (v.)

"to make untidy, put in a state of disorder," 1837, American English, probably a variant of mess in its sense of "to disorder." It was attested earlier (1830) as a noun meaning "disturbance, state of confusion." Related: Mussed; mussing.

Related entries & more 
environmentalism (n.)
1923, as a psychological theory (in the nature vs. nurture debate), from environmental + -ism. The ecological sense is from 1972. Related: Environmentalist (n.), 1916 in the psychological sense, 1970 in the ecological sense.
Related entries & more 
introverted (adj.)
1781, "directed inward" (of the mind, etc.), past-participle adjective from introvert (v.). Psychological sense is from 1915. Other adjectives in the non-psychological sense were introversive (1820), introvertive (1846), introverse (1874).
Related entries & more 
psycho (adj.)
1927, shortening of psychological; 1936 (Raymond Chandler) as shortening of psychopathic (adj.).
Related entries & more