1 awful, horrible, horrid, horrific, horrendous, horrifying, hideous, ugly, nightmarish, dreadful, heinous, grisly, gruesome, disgusting, nauseous, nauseating, repulsive, repellent, revolting, frightful, grotesque, hellish, ghoulish, freakish, fiendish, barbaric, barbarous, savage, inhuman, merciless, ruthless, brutal, brutish, beastly:
How could anyone treat another human being with such monstrous cruelty!
2 outrageous, shocking, scandalous, atrocious, appalling, wicked, villainous, evil, vile, insensitive, cruel, base, debased, shameful, shameless, infamous, disgraceful, nefarious, egregious, foul, vicious, flagitious, loathsome, depraved:
It is monstrous to suggest that money could compensate for the loss of a child. It was a monstrous trick to make him think he had failed the exam when he'd got the top mark
3 gigantic, giant, huge, vast, enormous, colossal, monster, gargantuan, jumbo, immense, tremendous, titanic, prodigious, massive, towering, elephantine, mammoth:
They are planning to build a monstrous shopping mall in the town centre.