Something that's terribly bad is dreadful. Some people love going to the opera, but for others there's no more dreadful way to spend three hours.
Dreadful means "full of dread," "feeling a sense of dread," or "causing dread." Dread means fear or anxiety. The adjective dreadful can describe something truly devastating, like the dreadful aftermath of a tornado, or something that's awful on a more personal level, like a dreadful blind date. If it's bad, fearsome, or unpleasant, you can call it dreadful.
