late 14c., "inordinate self-esteem, arrogance," especially "self-satisfaction over one's accomplishments or qualities, vainglory" (early 15c.), from Old French elacion "elation, conceit, arrogance, vanity," from Latin elationem (nominative elatio) "a carrying out, a lifting up," noun of action from elatus "elevated," form used as past participle of efferre "carry out, bring out, bring forth, take away," from assimilated form of ex "out" (see ex-) + lātus "carried, borne" (see oblate (n.)), past participle of the irregular verb ferre "carry" (from PIE root *bher- (1) "to carry," also "to bear children"). Metaphoric sense of "a lifting of spirits" was in Latin and has always been the principal meaning in English. More positive sense of "buoyancy, joyfulness" is from 1750 in English.
a complicated word of uncertain history. First attested late 15c. in the sense "lewd person" (of either sex; since c. 1700 applied exclusively to women); probably [Middle English Compendium] from Old French baud "gay, licentious" (from Frankish *bald "bold" or some such Germanic source; see bold), despite the doubts of OED. The 15c. English word perhaps is a shortening of baude-strote "procurer or procuress of prostitutes" (c. 1300).
For the French sense evolution from "bold" to "lewd," compare Old French baudise "ardor, joy, elation, act of boldness, presumption;" baudie "elation, high spirits," fole baudie "bawdry, shamelessness." The Old French word also is the source of French baudet "donkey," in Picardy dialect "loose woman."
The second element in baude-strote would be trot "one who runs errands," or Germanic *strutt (see strut (v.)). There was an Old French baudestrote, baudetrot of the same meaning (13c.), and this may be the direct source of Middle English baude-strote. The obsolete bronstrops "procuress," frequently found in Middleton's comedies, probably is an alteration of baude-strote.
Used by 17c. mystical writers for "a state of rapture that stupefied the body while the soul contemplated divine things," which probably helped the meaning shift to "exalted state of good feeling" (1610s). Slang use for the drug 3,4-methylendioxymethamphetamine dates from 1985. Formerly also spelled ecstasie, extacy, extasy, etc. Attempts to coin a verb to go with it include ecstasy (1620s), ecstatize (1650s), ecstasiate (1823), ecstasize (1830).