This isn't a terrible idea; it just doesn't have much to do with anything else going on here.

So I've been thinking it wouldn't be such a terrible idea to make a phone call or two.

It was part of a terrible idea to open up the book club to the men in our lives.

Yet another example that trying to be good to people is generally a terrible idea.

But why couldn't he see what a terrible idea it was?

I agree with most that this is a terrible idea.

It didn't seem like such a terrible idea to him.

But his older brother thought that was a terrible idea.

Oh, and yeah the bill looks like a terrible idea.

Using the military for this purpose would be a terrible idea.