She grew cautious at this admission, and felt the need to explain.

But Harry could tell they were growing more cautious.

He was about to say something but grew cautious.

As a result, the league has grown exceedingly cautious, again.

I would say he grew immensely cautious, and began to think of the future.

After a moment Eric shot; a miss this time, but a close one, and the enemy grew cautious.

She'd know about the latter two, by reputation if nothing else, and now her eyes grew cautious once more.

I've grown a bit cautious about things that aren't possible.

She seemed to have grown cautious in the last hour.

But other group members who had been technology enthusiasts grew more cautious.