in silence
Without making a noise, silently.
The cat crept down the stairs in silence.
First and foremost, the monk should own nothing in this world, but he should have as his possessions solitude of the body, modesty of bearing, a modulated tone of voice, and a well-ordered manner of speech. He should be without anxiety as to his food and drink, and should eat in silence. Basil of Caesarea
Great souls endure in silence. Friedrich Schiller
The cruelest lies are often told in silence. Robert Louis Stevenson
The Potato grows in silence, The iron corrodes in silence. Malay Proverb
A judge and a stomach do their asking in silence. Russian Proverb
Love and let the world know, hate in silence. Egyptian Proverb