is a specific kind of: unpleasantness.

is a broader term that covers: frightfulness.

derivation: dreadful | awful, dire, direful, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible | abominable, atrocious, awful, dreadful, painful, terrible, unspeakable | horrid | severe, terrible, wicked | awful, nasty | hideous, horrid, horrific, outrageous | awful, frightful, terrible, tremendous.