slack-jawed

listen to the pronunciation of slack-jawed
Englisch - Türkisch
gevşek çeneli
Englisch - Englisch
Overly talkative; indiscreet

Spencer was one of those slack-jawed youths who are constitutionally incapable of preserving a secret.

Unsophisticated or unthinking; dimwitted in appearance

But driving a car—particularly the supersize models—really should demand more concentration than, say, slouching slack-jawed in front of the wide screen in your den.

With the mouth in an open position and the jaw hanging loosely, especially as indicating bewilderment or astonishment

For one frightful moment there was no sound; even the men's breathing was hushed, and they sat slack-jawed, stunned, half-minded to believe this some hideous, incredible jest.

If you say that someone is slack-jawed, you mean that their mouth is hanging open, often because they are surprised. He just gazed at me slack-jawed. having your mouth slightly open, especially because you are surprised or stupid = open-mouthed