noiseless

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

The snow was light and noiseless as it floated down. 雪花静悄悄地轻轻飘落下来。

2. noiselesslyADV

I shut the door noiselessly behind me. 我把身后的门轻轻带上。