Someone who is silent is not speaking.
If you describe someone as a silent person, you mean that they do not talk to people very much, and sometimes give the impression of being unfriendly.
A place that is silent is completely quiet, with no sound at all. Something that is silent makes no sound at all.
If someone is silent about something, they do not tell people anything about it, because they think it is a private matter or because they want to keep the information secret.
A silent emotion or action is not expressed in speech.
A silent film has pictures usually accompanied by music but does not have the actors' voices or any other sounds.
A silent letter in a word is written but not pronounced. For example, the 'k' in the word 'know' is silent.