Synonyms for Mournful:

adj.

all (adjective)
plaintive.
dejected (adjective)
despondent, blue, anxious, gloomy, sullen, woeful, dejected, melancholy, grim, downhearted, anguished, pensive, plaintive, discouraged, heartbroken, morose, contemplative, disconsolate, dreary, lachrymose, sad, depressed, moody, wistful, disheartened, dolorous, glum, overcome, joyless, miserable, despairing, dispirited.
depressing (adjective)
bleak.
doleful (adjective)
doleful, painful.
regretful (adjective)
rueful.
sorrowful (adjective)
disconsolate, doleful, woeful, sad, anguished, forlorn, heartbroken, depressed, grievous, distressing.
woebegone (adjective)
woebegone.

n.

upsetting, tragic, forlorn, unhappy, painful, terrible, mourning. distressing, homesick, bleak, subdued. grievous, regrettable, deplorable. mournful (noun)
plaintive, sad, doleful, sorrowful.

Other synonyms:

bleak. grievous, regrettable. rueful, woebegone, deplorable. dismal
lugubrious.
sorrowful
sorrowful.

Usage examples for mournful

  1. Cutter was interested in Gregorios, and asked him a great many questions, so that Chrysophrasia felt she was being neglected, and wore her most mournful expression. – Paul Patoff by F. Marion Crawford
  2. Blucher looked after him with a mournful glance and a deep sigh. – NAPOLEON AND BLUCHER by L. Muhlbach
  3. The mournful hooting of great owls sounded from the woods, with now and then the cry of a night bird, or shriek of wounded bird. – Annie o' the Banks o' Dee by Gordon Stables