grievous

Synonyms: afflicting agonizing appalling atrocious calamitous damaging deplorable dire dismal disquieting distressing disturbing dreadful egregious flagrant glaring grave harmful heart-rending heavy heinous hurtful injurious intolerable lamentable monstrous mournful offensive onerous oppressive outrageous pathetic pitiful sad shameful sharp shocking sorrowful taxing tough tragic troublesome unbearable upsetting villainous weighty wounding

Antonyms: good harmless pleasant