Causing or able to cause fear
He thought it would be dreadful for me.
I'm sure she caught that dreadful disease from one of them and it killed her.
She is the third to do so since I've been in this dreadful place.
So dreadful had been the yoke of Rome, which they had shaken off, that they feared to submit to anything similar even under Protestant auspices.
It would be dreadful to eat these dear little things.