direful

1. Inspiring dread; terrible.
2. Foreshadowing evil or disaster; ominous.

adjective

1. Causing or able to cause fear: appalling, dire, dreadful, fearful, fearsome, formidable, frightful, ghastly, redoubtable, scary, terrible, tremendous. See fear/courage.
2. Portending future disaster: apocalyptic, apocalyptical, baneful, dire, fateful, fire-and-brimstone, grave², hellfire, ominous, portentous, unlucky. See luck/misfortune/chance, warn/invite.

Definition: fearful; horrible
Antonyms: good, nice

The adjective has one meaning:

Meaning #1: causing fear or dread or terror
  Synonyms: awful, dire, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible