"Don't you think she's a little young to've made such formidable enemies already?"

Because they have all the technology this makes them a very formidable enemy, and not one to be taken lightly.

Now, time is an even more formidable enemy, and so is the law.

She's one of the most formidable enemies we could face.

We couldn't have a more formidable enemy than the people who really do know how to use this ship.

Supplements may be questionable, but heat remains the most formidable enemy.

People should understand it is a formidable enemy to have.

She would be a formidable enemy, Tenar thought, and was a difficult friend.

I believe they are in the service of some much more formidable enemy.

But he did not anticipate that a formidable enemy would threaten him from the south.