Noiseless

Holmes had picked up the powerful air-gun from the floor, and was examining its mechanism. "An admirable and unique weapon," said he, "noiseless and of tremendous power."

Walking somewhat slowly by reason of his concentration, the boy—an ancient man in some phases of thought, much younger than his years in others—was overtaken by a light-footed pedestrian, whom, notwithstanding the gloom, he could perceive to be wearing an extraordinarily tall hat, a swallow-tailed coat, and a watch-chain that danced madly and threw around scintillations of sky-light as its owner swung along upon a pair of thin legs and noiseless boots.

The movements of the cat were noiseless as it approached the mousehole.

For by the hearth the children sit ⁠Cold in that atmosphere of Death, ⁠And scarce endure to draw the breath, Or like to noiseless phantoms flit: But open converse is there none, […]

The core idea of the Nostega paradign is basically camouflaging messages by embedding them in a form of noiseless data by employing either altered authenticated data or legitimate untraceable data, as shown in Section 1.3.