dismalyoudaoicibaDictYouDict[dismal 词源字典]
dismal: [13] Etymologically, dismal means ‘bad day’. It comes, via Anglo-Norman dis mal, from Latin diēs malī, literally ‘evil days’, a term used to denote the two days in each month which according to ancient superstition were supposed to be unlucky (these days, of set date, were said originally to have been computed by Egyptian astrologers, and were hence also called Egyptian days). The term dismal thus acquired connotations of ‘gloom’ and ‘calamity’. Its earliest adjectival use, somewhat tautologically, was in the phrase dismal day, but in the late 16th century it broadened out considerably in application.
[dismal etymology, dismal origin, 英语词源]
dismal (adj.)youdaoicibaDictYouDict
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.