Still waters run deep

Cultural  

1. A person's calm exterior often conceals great depths of character, just as the deepest streams can have the smoothest surfaces.

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still waters run deep Idioms  

1. A quiet person may be very profound, as in Susie rarely says much, but still waters run deep. The physical observation in this term dates from ancient times, but it has been used figuratively since about 1400. Anthony Trollope amplified it in He Knew He Was Right (1869): “That's what I call still water. She runs deep enough. . . . So quiet, but so—clever.”

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Example Sentences

But the larger problem for Bentley was trying to get inside the head of a logger who’s the very definition of “still waters run deep.”

From Los Angeles Times

“Will miss your dulcet tones. Forever lucky to have gone on such a journey with you. Ringside seat. You were so funny to me and the epitome of still waters run deep. I will always cherish our conversations, often with me hanging in your doorway barring your exit, and the insane opportunity to be your sidekick. - “

From Washington Times

Still waters run deep, indeed.

From Salon

She’s a still waters run deep kind of woman, and I loved that about her.

From Los Angeles Times

But still waters run deep, or so we might imagine of her.

From Los Angeles Times