without any sound

The empty house was completely silent. 那座空房子一片寂静。

literary It was four o'clock in the morning and the streets were as silent as the grave (= completely silent). 那是凌晨四点，街道如坟墓一样寂静。

without talking

She whispered a silent prayer that her wounded brother would not die. 她默默地祷告，希望她受伤的兄弟不会死去。

The police officer told the criminal that he had the right to remain silent. 警官告诉罪犯他有权保持沉默。

He was silent on/about his plans for the future. 他对将来的打算保持沉默。

Arthur has always been the strong, silent type (= a type of person who says very little). 阿瑟一直是那种坚强而沉默的人。

a setting on an electronic device that stops it from making a noise when it receives a message

The show's about to start so I'm putting my phone on silent. 演出马上开始了，我把电话改到了静音。