noiseless

1. ADJ Something or someone that is noiseless does not make any sound. 無聲的[ADV with v]

The snow was light and noiseless as it floated down. 雪花靜悄悄地輕輕飄落下來。

2. noiselesslyADV

I shut the door noiselessly behind me. 我把身後的門輕輕帶上。