Its meaning: ‘Still waters run deep,’ says the proverb. Another proverb says ‘Still water run smooth’. It means that a man of sterling qualities has no pretensions. A person of extra-ordinary and exceptional talent is often found to be very quiet and humble in his behavior.
It also means that the gentle (and quite) exterior behavior often hides the passionate nature of a person.
Origin: The origin of this proverb is generally believed to be an old Latin proverb that says, ‘altissima quaeque flumina minimo sono labi’ that literally means that “the deepest rivers flows with minimum noise”.
Explanation: The water at the surface of deep-sea are often very still. We cannot accurately guess the depth of a sea by looking at the water at the surface. Similarly, we should not judge a person by looking at his exterior appearance.
A person with simple and modest behavior may be a person of great learning. People cannot judge his competence with his external appearance.
However, a ripe scholar does not make a show of his learning. Unless it is sought, he does not force opinion on others.
Newton was a great scientist. However, he spoke of himself as gathering pebbles on the seashore while the great ocean of learning lay in front of him.
A man, who knows little, becomes vain and boastful. However, the man who possesses depth of learning is humble and keeps himself in the background.
Note: The above proverb, ‘still waters run deep’ is mostly used to describe ‘the positive qualities of passionate and learned people’. However, on few occasions, this proverb is also used to warn that ‘behind simple and humble exterior appearance of a person, there may exist a deceitful character’. Hence, people should exercise caution while dealing with unknown people.