A lot of adjectives are made from verbs by adding -ing or -ed:
The commonest -ing adjectives are:
If you say something is interesting, you mean it interests you:
I read a very interesting article in the newspaper today.
If you say something is terrifying, you mean it terrifies you:
That Dracula film was absolutely terrifying.
The commonest -ed adjectives are:
If something bores you, you can say you feel bored.
We had nothing to do. We were really bored.
If something terrifies you, you can say you are terrified.
I didn't really enjoy the Dracula film. Most of the time I was terrified.