Synonyms of 'abysmal'

abyssal, appalling, Atlantean, awful, bottomless, Brobdingnagian, cavernous, colossal, Cyclopean, dreadful, elephantine, enormous, epic, fathomless, gargantuan, giant, gigantic, herculean, heroic, Homeric, huge, illimitable, immense, infinite, jumbo, mammoth, mighty, monster, monstrous, monumental, mountainous, plumbless, prodigious, profound, soundless, stupendous, terrible, titanic, towering, tremendous, unfathomable, unfathomed, unsounded, vast, yawning