Middle English cursen, from Old English cursian, "to wish evil to; to excommunicate," from the source of curse (n.). Intransitive meaning "swear profanely, use blasphemous or profane language" is from early 13c. (compare swear (v.)). The sense of "blight with malignant evils" is from 1590s. Related: Cursed; cursing.
late Old English curs "a prayer that evil or harm befall one; consignment of a person to an evil fate," of uncertain origin. No similar word exists in Germanic, Romance, or Celtic. Middle English Compendium says probably from Latin cursus "course" (see course (n.)) in the Christian sense "set of daily liturgical prayers" extended to "set of imprecations" as in the sentence of the great curse, "the formula read in churches four times a year, setting forth the various offenses which entailed automatic excommunication of the offender; also, the excommunication so imposed." Connection with cross is unlikely. Another suggested source is Old French curuz "anger."
Meaning "the evil which has been invoked upon one, that which causes severe trouble" is from early 14c. Curses as a histrionic exclamation ("curses upon him/her/it") is by 1680s. The curse in 19c. was the sentence imposed upon Adam and Eve in Genesis iii.16-19. The slang sense "menstruation" is from 1930. Curse of Scotland, the 9 of diamonds in cards, is attested from 1791, but the signification is obscure.
also curst, c. 1200, "under a curse, damned," past-participle adjective from curse (v.). From late 14c. as an expletive. Related: Cursedly; cursedness.
also accurst, early 13c., acursede "being under a curse," past-participle adjective from obsolete verb acursen "pronounce a curse upon, excommunicate" (late 12c.), from a- intensive prefix (see a- (1)) + cursein "to curse" (see curse (v.)). The unetymological -c- is 15c., a mistaken Latinism in imitation of words in acc-. The weakened sense of "worthy of a curse, damnable" is from 1590s. Related: Accursedly; accursedness.
1815, "to say bad words, use profane language," a vulgar pronunciation of curse (v.). The transitive sense of "to curse, swear at" is by 1838. Related: Cussed; cussing. To cuss (someone) out is attested by 1881.
The loss of -r- before -s- is not uncommon: Compare arse/ass (n.2), burst/bust, horse/hoss, barse/bass, garsh/gash, parcel/passel.
late 14c., "cursing, act of laying under a curse," from Latin execrationem (nominative execratio) "malediction, curse," noun of action from past-participle stem of execrari "to hate, curse," from ex "out" (see ex-) + sacrare "to devote to holiness or to destruction, consecrate," from sacer "sacred" (see sacred). From 1560s as "an uttered curse."
"to curse, imprecate evil upon," hence "to detest utterly, abominate," 1560s, from Latin execratus/exsecratus, past participle of execrari/exsecrari "to curse, utter a curse, take a solemn oath with imprecations; hate, abhor," from ex "out" (see ex-) + sacrare "to devote to" (see sacred). Hence, "to devote off or away; to curse." Compare consecrate. Related: Execrated; execrating.
"a curse," mid-13c., from Old French maleiçon "curse," from Latin maledictionem "the action of speaking evil of, slander," in Late Latin "a curse," noun of action from past participle stem of maledicere "to speak badly or evil of, slander," from male "badly" (see mal-) + dicere "to say" (from PIE root *deik- "to show," also "pronounce solemnly").
mid-15c., malediccion, "a curse; condemnation, excommunication," from Old French maledicion "a curse" (15c.) and directly from Latin maledictionem (nominative maledictio) "the action of speaking evil of, slander," in Late Latin "a curse," noun of action from past participle stem of maledicere "to speak badly or evil of, slander," from male "badly" (see mal-) + dicere "to say" (from PIE root *deik- "to show," also "pronounce solemnly"). By 1530s as "evil-speaking, cursing, reviling."