The girl gave her a vacant grin and shrugged.

I feel that even in my sleep I have a vacant grin on my face.

What are you doing, sitting out there with a silly vacant grin on your face?

And that was when I became suspicious for all had stupid, vacant grins on their faces.

A vacant grin on his face, eyes glazed, he rolled his head from side to side, mumbling incessantly.

On close inspection, though, there's a lot more intelligence at work in Bill and Ted's happy-go-lucky witlessness, and in Mr. Reeves's vacant grin, than in anything as authentically dopey and one-dimensional as, say, the current "Medicine Man."

He sat there with a vacant grin, enjoying her ministrations, accepting them as his due.

At first J was about to grin at her with the vacant grin he reserved for all small children who insisted on being noticed by him, then the thought entered his mind, Are you Dane Colby?