Synonyms for Upsetting:

adj.

aggravating (adjective)
aggravating, disturbing, antagonizing, exasperating, bothersome, inflaming, Bedeviling, Enraging, tormenting, grating, infuriating, irritating, pestering, perturbing, troublesome, annoying, Harassing, Rankling, Irksome, vexing, teasing, exacerbating.
disagreeable (adjective)
unhappy.
disturbing (adjective)
disquieting, vexing, worrisome, irritating, Harassing, troublous, distressing, unsettling, annoying, painful, bothersome, intrusive, troubling, disconcerting, agitating, Discomposing, aggravating, distressful, Irksome, depressing, troublesome, perturbing, disruptive.
revolutionary (adjective)
revolutionary, upheaving, mutinous, rebellious, restructuring.

n.

upsetting (noun)
disconcerting, displeasing.

v.

aggravating (verb)
Bothering, Fretting, nagging, irking, Arousing, Discomposing, troubling, baiting, needling, hassling, peeving, chafing, Harrying, Envenoming, badgering.
agitating (verb)
quaking, shaking, jarring, stirring, palpitating, quavering, jolting, churning, twitching, shuddering, Flustering, disquieting, shivering, quivering, agitating.
deranging (verb)
tossing, Blurring, meddling, rippling, swirling, Displacing, Scrambling, Roughening, fermenting, Botching, confounding, Disorganizing, Convulsing, mixing up, Mussing, tampering, Rumpling, tousling, tumbling, Mislaying, scattering, Hashing, Misplacing, Muddling, Cluttering, capsizing, confusing, whipping, Disarranging, Deranging, Rummaging, Disordering, roiling, Messing, Ruffling, Jumbling, Disheveling, Dislocating, Whisking.
inverting (verb)
Inverting, Transposing, upturning, Reversing, changing, Overturning, upending.
revolting (verb)
Mutinying, shaking up, rebelling, revolting, Overthrowing.

Other synonyms:

disruptive, distressing, worrisome, unsettling, miserable, troublous, unhappy, depressing, distressful, heartbreaking. dismal, intrusive, tragic, painful. sad, terrible. Other relevant words:
distressful, intrusive, disruptive, unsettling, depressing, heartbreaking, tragic, displeasing, dismal, sad, disconcerting, troublous, terrible, painful, miserable, worrisome, pain, unhappy, distressing.

Usage examples for upsetting

  1. " Well," said Henley, his flush of anger giving way to one of genuine embarrassment, " he was upsetting business, Mrs. Cartwright. – Dixie Hart by Will N. Harben
  2. I got to think that your Lordship was upsetting – The Duke's Children by Anthony Trollope