Online Etymology Dictionary

dismal (adj.): c. 1400, from Anglo-French dismal (mid-13c.), from Old French (li) dis mals "(the) bad days," from Medieval Latin dies mali "evil or unlucky days" (also called dies Ægyptiaci), from Latin dies "days" (see diurnal) + mali, plural of malus "bad" (see mal-).

Through the Middle Ages, calendars marked two days of each month as unlucky, supposedly based on the ancient calculations of Egyptian astrologers (Jan. 1, 25; Feb. 4, 26; March 1, 28; April 10, 20; May 3, 25; June 10, 16; July 13, 22; Aug. 1, 30; Sept. 3, 21; Oct. 3, 22; Nov. 5, 28; Dec. 7, 22). Modern sense of "gloomy, dreary" first recorded in English 1590s, in reference to sounds. Related: Dismally.
dismantle (v.): 1570s, from Middle French desmanteler "to tear down the walls of a fortress," literally "strip of a cloak," from des- "off, away" (see dis-) + manteler "to cloak" (see mantle). Related: Dismantled; dismantling.
dismast (v.): 1747, from dis- + mast (n.1). Related: Dismasted; dismasting.
dismay (v.): late 13c., dismaien, from Old French *desmaier (attested only in past participle dismaye), from Latin de- intensive prefix + Old French esmaier "to trouble, disturb," from Vulgar Latin *exmagare "divest of power or ability" (source of Italian smagare "to weaken, dismay, discourage"), from ex- (see ex-) + Germanic stem *mag- "power, ability" (source also of Old High German magen "to be powerful or able;" see may (v.)). Spanish desmayer "to be dispirited" is a loan word from Old French. Related: Dismayed; dismaying.
dismay (n.): c. 1300, from dismay (v.).
dismember (v.): c. 1300, from Old French desmembrer (11c.), from Medieval Latin dismembrare "tear limb from limb; castrate," from Latin de- "take away" + membrum "limb" (see member). Related: Dismembered; dismembering.
dismemberment (n.): 1751, from dismember + -ment. Earlier formation was dismembration (1590s).
dismiss (v.): early 15c., from Latin dimissus, past participle of dimittere "send away, send different ways; break up, discharge; renounce, abandon," from dis- "apart, away" (see dis-) + mittere "send, let go" (see mission). Prefix altered by analogy with many dis- verbs. Dismit, in the same sense, is attested from late 14c. Related: Dismissed; dismissing.
dismissal (n.): 1806, formed on model of refusal, etc., from dismiss + -al (2); replacing earlier dismission (1540s).
dismissive (adj.): 1640s, "characterized by or appropriate to dismissal;" from dismiss + -ive. Meaning "contemptuous, rejecting" is recorded by 1922. Related: Dismissively.
dismount (v.): 1540s, from dis- + mount (v.). Related: Dismounted; dismounting.
Disney: surname attested from mid-12c. (William de Ysini), from Isigny in the Calvados region of Normandy. Disneyesque, in reference to Walt Disney's cartooning style, is attested from 1939 (in W.H. Auden).
Disneyland (n.): in figurative sense of "land of make-believe" first recorded 1956, from U.S. entertainment park (opened in 1955) created by cartoonist Walter E. Disney (1901-1966).
disobedience (n.): c. 1400, from Old French desobedience, from Vulgar Latin *disobedientia (replacing Latin inobedientia) from Latin dis- (see dis-) + obedientia (see obedience). The English word replaced earlier desobeissance in this sense, and inobedience (c. 1200).
disobedient (adj.): early 15c., dysobedyent, from Old French desobedient, from Vulgar Latin *disobedientem (replacing Latin inobedientem) from Latin dis- (see dis-) + obedientem (see obedient). Related: Disobediently. Earlier in the same sense was disobeissant (late 14c.), from Old French desobeissant, and inobedient (early 14c.).
disobey (v.): late 14c., from Old French desobeir (13c.) "disobey; refuse service or homage," from Vulgar Latin *disoboedire, reformed with dis- from Late Latin inobedire, a back-formation from inobediens "not obeying," from Latin in- "not" + present participle of obedire (see obey). Related: Disobeyed; disobeying.
disoblige (v.): c. 1600, "to free from obligation;" 1630s, "to refuse to oblige," from French désobliger (c. 1300), from des- (see dis-) + Latin obligare (see oblige). Related: Disobliged; disobliging.
disorder (v.): late 15c., from dis- "not" (see dis-) + the verb order (v.). Replaced earlier disordeine (mid-14c.), from Old French desordainer, from Medieval Latin disordinare "throw into disorder," from Latin ordinare "to order, regulate" (see ordain). Related: Disordered; disordering.
disorder (n.): 1520s, from disorder (v.).
disorderly (adj.): 1580s, "opposed to moral order," also "opposed to legal authority;" see dis- + orderly (adj.). The meaning "untidy" is attested from 1630s; the older senses are those in disorderly house, disorderly conduct, etc.
disorganize (v.): 1793, from French désorganiser, from dés- "not" (see dis-) + organiser "organize" (see organize). This word and related forms were introduced in English in reference to the French Revolution. Related: Disorganized; disorganizing; disorganization.
disorient (v.): 1650s, from French désorienter "to cause to lose one's bearings," literally "to turn from the east," from dés- (see dis-) + orienter (see orient (v.)). Related: Disoriented; disorienting.
disorientation (n.): 1860; see dis- + orientation.
disown (v.): 1620s; see dis- + own (v.) in the sense "be responsible for, have legal authority over (and thus legal liability for)." Related: Disowned; disowning.
disparage (v.): early 14c., "degrade socially," from Old French desparagier (Modern French déparager) "reduce in rank, degrade, devalue, depreciate," originally "to marry unequally," and thus by extension the disgrace or dishonor involved in this, from des- "away" (see dis-) + parage "rank, lineage" (see peer (n.)). Sense of "belittle" first recorded 1530s. Related: Disparaged; disparaging; disparagingly.
disparagement (n.): late 15c., from Old French desparagement, from desparagier (see disparage).
disparate (adj.): c. 1600, "unlike in kind," from Latin disparatus, past participle of disparare "divide, separate," from dis- "apart" (see dis-) + parare "get ready, prepare" (see pare); meaning influenced by Latin dispar "unequal, unlike." Related: Disparately; disparateness.
disparity (n.): 1550s, from Middle French disparité (16c.), from Late Latin disparitatem (nominative disparitas) "inequality," from dis- "not" (see dis-) + paritas "parity" (see parity). Related: Disparities.
dispassionate (adj.): 1590s, from dis- "the opposite of" (see dis-) + passionate. Related: Dispassionately.
dispatch (v.): 1510s, "to send off in a hurry," from a word in Spanish (despachar "expedite, hasten") or Italian (dispacciare "to dispatch"). For first element, see dis-. The exact source of the second element has been proposed as Vulgar Latin *pactare "to fasten, fix" or *pactiare, or as Latin -pedicare "to entrap" (from Latin pedica "shackle;" see impeach); and the Spanish and Italian words seem to be related to (perhaps opposites of) Old Provençal empachar "impede." See OED for full discussion. Meaning "to get rid of by killing" is attested from 1520s. Related: Dispatched; dispatching. As a noun, from 1540s, originally "dismissal;" sense of "a message sent speedily" is first attested 1580s.
dispatcher (n.): mid-16c., agent noun from dispatch (v.).
dispel (v.): c. 1400, dispelen, from Latin dispellere "drive apart," from dis- "away" (see dis-) + pellere "to drive, push" (see pulse (n.1)). Since the meaning is "to drive away in different directions" it should not have as an object a single, indivisible thing (you can dispel suspicion, but not an accusation). Related: Dispelled; dispelling.
dispensable (adj.): 1530s, "subject to dispensation," from Medieval Latin dispensabilis, from Latin dispensare "disburse, administer, distribute (by weight)" (see dispense). Meaning "that can be done without" is from 1640s. Related: Dispensability.
dispensary (n.): "place for weighing out medicines," 1690s, from Medieval Latin dispensarius "one who dispenses," from Latin dispensare "disburse, administer, distribute (by weight)" (see dispense).
dispensation (n.): late 14c., from Old French despensacion (12c., Modern French dispensation), or directly from Latin dispensationem (nominative dispensatio) "management, charge," noun of action from past participle stem of dispensare "disburse, administer, distribute (by weight)" (see dispense). Theological sense is from the use of the word to translate Greek oikonomoia "office, method of administration."
dispense (v.): early 14c., from Old French dispenser "give out" (13c.), from Latin dispensare "disburse, administer, distribute (by weight)," frequentative of dispendere "pay out," from dis- "out" (see dis-) + pendere "to pay, weigh" (see pendant).

In Medieval Latin, dispendere was used in the ecclesiastical sense of "grant licence to do what is forbidden or omit what is required" (a power of popes, bishops, etc.), and thus acquired a sense of "grant remission from punishment or exemption from law," hence "to do away with" (1570s), "do without" (c. 1600). Older sense is preserved in dispensary. Related: Dispensed; dispensing.
dispenser (n.): c. 1400, "one who administers" (a household, etc.), c. 1200 in surnames, from Anglo-French dispensour, Old French despenseor, from Latin dispensatorem, agent noun from dispensare "disburse, administer, distribute (by weight)" (see dispense). Meaning "a container that dispenses in fixed measure" is from 1918.
dispersal (n.): 1821; see disperse + -al (2).
disperse (v.): late 14c., from Latin dispersus, past participle of dispergere "to scatter," from dis- "apart, in every direction" (see dis-) + spargere "to scatter" (see sparse). The Latin word is glossed in Old English by tostregdan. Related: Dispersed; dispersing.
dispersion (n.): late 14c., from Old French dispersion (13c.), from Latin dispersionem (nominative dispersio) "a scattering," noun of action from past participle stem of dispergere (see disperse).
dispirit (v.): 1640s; see dis- + spirit (n.). Related: Dispirited; dispiriting.
displace (v.): 1550s, from Middle French desplacer (15c.), from des- (see dis-) + placer "to place." Related: Displaced; displacing. Displaced person "refugee" is from 1944.
displacement (n.): 1610s, "removal from office;" see displace + -ment. Physics sense is from c. 1810.
display (v.): late 13c., "unfurl" (a banner, etc.), from Old French desploiir (Modern French déployer) "unfold, unfasten, spread out" (of knots, sealed letters, etc.), from Latin displicare "to scatter," from dis- "un-, apart" (see dis-) + plicare "to fold" (see ply (v.1)).

Properly of sails or flags (and unconnected to play); meaning "reveal, exhibit" is late 14c. Related: Displayed; displaying.
display (n.): 1580s, "description," from display (v.). Meaning "exhibition" is from 1680s.
displease (v.): early 14c., from Old French desplais-, present tense stem of desplaisir "to displease" (13c.), from Latin displicere "displease," from dis- "not" (see dis-) + placere "to please" (see please). Related: Displeased; displeasing.
displeasure (n.): early 15c., from Old French desplaisir, infinitive used as a noun (see displease). Earlier in same sense was displesaunce (late 14c.).
disport (v.): late 14c., from Anglo-French disporter "divert, amuse," from Old French desporter "to seek amusement," literally "carry away" (the mind from serious matters), from des- "away" (see dis-) + porter "to carry," from Latin portare "to carry" (see port (n.1)). Compare disporter "a minstrel or jester" (early 15c.).
disposable (adj.): 1640s, "that may be done without;" see dispose + -able. Meaning "designed to be discarded after one use" is from 1943, originally of diapers, soon of everything; replaced throw-away (1928) in this sense. First recorded use of disposable income (preserving the older sense) is from 1948.
disposal (n.): 1620s, "power to make use of;" see dispose + -al (2); of waste material, from c. 1960, originally in medical use.