Synonyms for Sadly:

adv.

all (adverb)
unhappily.
dejectedly (adverb)
gloomily, miserably, pensively, plaintively, grimly, moodily, melancholically, despairingly, joylessly, glumly, anxiously, dejectedly, dolorously, woefully, downheartedly, morosely, wistfully, sullenly, Contemplatively, drearily, despondently, disconsolately, mournfully.
regretfully (adverb)
sorrowfully.
unhappily (adverb)
dolefully, morosely, grievously, dejectedly, sorrowfully, joylessly, wistfully, cheerlessly, gloomily, dismally.

adv

deeply (adverb)
mournfully.
dejectedly (adverb)
gloomily, miserably, pensively, plaintively, grimly, moodily, melancholically, despairingly, joylessly, glumly, anxiously, dejectedly, dolorously, woefully, downheartedly, morosely, wistfully, sullenly, Contemplatively, drearily, despondently, disconsolately, mournfully.
hopelessly (adverb)
despairingly, despondently, disconsolately, gloomily, dejectedly, dismally.
regretfully (adverb)
sorrowfully.
regrettably (adverb)
unhappily.

n.

heartbreaking, terrible, dismal, upsetting, tragic, depressing, painful. hopelessly, sorry, unspeakable, utterly, thorough, utter, downright, excruciating, such as it is. melancholy, subdued, sad, gloomy, unhappy, sorrowful, wistful, bleak, miserable, homesick. sadly (noun)
unhappily, woefully, lamentably, deplorably.
unhappily (noun)
dismally, dolefully, grievously, in sorrow, cheerlessly, sorrowfully.

Other synonyms:

hopelessly. unspeakable, excruciating, sorry. Other relevant words:
gloomy, deplorably, depressing, homesick, miserable, melancholy, sorrowfully, bleak, unhappy, upsetting, dismally, unspeakable, wistful, unhappily, grievously, subdued, downright, dolefully, cheerlessly, sorry, utter, painful, excruciating, tragic, lamentably, hopelessly, thorough, sorrowful, sad, dismal, terrible, utterly, heartbreaking.

Usage examples for sadly

  1. She looked up at him sadly and the tears stood in her eyes. – The Star-Gazers by George Manville Fenn
  2. He admitted it, rather sadly – Kildares of Storm by Eleanor Mercein Kelly
  3. I am afraid you have found him a sadly changed man? – The Legacy of Cain by Wilkie Collins