Synonyms of frightfulness

2 Syllables
monster, mutant, horror
3 Syllables
hideousness, eyesore, freakishness, heinousness, dreadfulness, awfulness, ghastliness, horridness, mutation, odiousness
4 Syllables
grotesqueness, gruesomeness, monstrosities, enormity, monstrosity, atrocity, deformity
5 Syllables
abnormality