drop one's guard

Now more than ever, she could not drop her guard.

"And because our crime rate is so low, they kind of drop their guard."

We never sense the moment in which she drops her guard.

He knew they would drop their guard, make a mistake.

But we mustn't drop our guard or be over confident.

Third, drop your guard and let someone do something for you.

He only just dropped his guard low enough, cutting the dog along its shoulder.

I didn't teach you to drop your guard so easily with anyone.

"Where security is concerned, you cannot ever drop your guard."

But at the cost of never being able to drop his guard completely.