Thesaurus

abominable, aggravated, alarming, appalling, atrocious, awful, bad, baleful, big, blood-and-guts, bloodcurdling, bonzer, chilling, cold, concentrated, consuming, corked, corky, crappy, creepy, creepy-crawly, deep, deplorable, dire, direful, dismaying, disobedient, distressing, dread, dreaded, dreadful, evil, exceeding, exceptional, exquisite, extraordinary, extraorinaire, extreme, fantastic, fearful, fearsome, fierce, forbidding, formidable, frightening, frightful, ghastly, grand, great, grim, grisly, gruesome, hair-raising, hairy, hard, hopeless, horrendous, horrible, horrid, horrific, horrifying, howling, icky, ill, immoderate, incomparable, incompetent, intemperate, intense, intensified, intensive, keen, lamentable, lousy, macabre, main, marvellous, marvelous, mediocre, menacing, minacious, minatory, mischievous, naughty, negative, nightmarish, no-good, olympian, ominous, one, overwhelming, painful, petrifying, phenomenal, pitiful, poor, preternatural, pretty, prodigious, profound, pyrotechnic, raging, rare, rattling, redoubtable, remarkable, rotten, rubber, sad, scarey, scary, screaming, severe, shivery, shuddery, sick, singular, sinister, smart, some, sorry, special, stinking, stinky, strong, stupefying, surpassing, swingeing, tearing, terrible, terrific, terrifying, thick, threatening, tough, tremendous, trigger-happy, ugly, unabated, uncanny, uncommon, uncomparable, uncool, unfavorable, unfavourable, unnerving, unskilled, unspeakable, unsuitable, unusual, utmost, uttermost, vehement, violent, wicked, wild, wonderful, wonderworking, wondrous, worse, worst

terrible is a ADJ.